Hmm...100 people, so it would need to be some sort of venue, and not someones house (unless they've got a freaking awesome house with that much space) needs to be...what, more than 40 hours, so a clean 48 hours would be good (just a solid 2 days of gaming)  The only issues I could see (aside from people just crapping out midway through) would be people needing to take care of various bodily functions.  Yeah, piss breaks wouldn't be too bad, especially if it's a big enough venue, but the kids won't be going to the pool anytime in those 2 days, so everyone would need to be prepared for that...issue.  Venue could range from random warehouse (if it's got the space/ability to house that many people/computers/whatever else is needed) which would probably also need some sort of restrooms brought in, to getting a hotels conference room, or some such thing (space/outlets/bathrooms available, and tables/chairs may be provided, but COST, and finding one that would allow a 2 day consecutive event)  The middle ground would probably be best, finding a location that could use it as publicity (home of the Guinness World Record LAN Party) and possibly sponsor the thing (or at least part of it) as that would make the food issues less than they would already start to be.  Food, being necessary for life, would be super important, and with only 5 min breaks allowed each hour, that food would most likely need to already be there, and readily available (unless there's food staff, just there to bring everyone their tacos and whatnot [don't know why I used TACOs as an example, they just seem like the kind of thing we should have people bringing to us while we game] who could also prepare foods, and take away the garbage and other junk)  If everyone was able to simply bring a cooler with their foodstuffs/beverages, then that would reduce the things to worry about, but then there's always the threat of running out, or the smell potential of stuff left out too long.  It will be smelly.  People will be rocking so much B.O. it isn't even funny (well, it is kinda funny, but only in theory, when you're there, you'll know the meaning of true suffering)  Every 8 hours or so, that 5 min break will be for people to re-up any anit-stank product they may be using, and for people to spray the air with something to lessen the extent of the rot smell that'll be creeping over everyone.  Air Conditioning.  These computers are going to make the place a sweaty pit of heat and rage, so AC is a huge must (to keep computers cool, and to lessen the pit stink that people will be developing throughout the days)  Changes of shirts will be super appreciated, along with plastic bags to house the tainted shirts from earlier in the event (only so much deoderant can do for that stinky shirt before it needs to hit the showers, changes of shirts=must)  This could be an issue for any ladies present (the whole shirt changing idea)  Maybe they just stink it up for the 40+ hours.  Maybe they aren't shy about it.  Maybe it's so dark (aside from monitor glow) that nobody really notices (also, dark gives more of an impression of cooler, even if it isn't really true for most lights used in these sorts of locales)

Wow, I just looked at what all I've been writing here (yay stream of thought writing!) and there's quite a bit.  Anyway, if I'm given enough notice (with what seems to be a year or so as the notice at the moment) I might actually be able to attend this, and partake of the madness (I think it would be a glasses weekend then, contacts for 48 hours is NOT a good idea)  More people means a greater split in costs (though less space per person, and more bodies/computers to stink/heat up the area) and a shinier record.  Also, key thing: we have to know that the people going in on this thing are committed to doing it.  No "well, I'll TRY to stay up", this is one of those all-or-nothing situations, and the people involved must be on the "all" side of things.  Last notes: Weekends are usually better, as people with "regular" jobs usually have those off; 3 or greater day weekends are great, as the folks with weekends off now have a 3rd day to get everything going, and most of the summer 3 days are around holidays that people are usually going off doing things in the outdoors (camping, BBQ, misc/other) and as such, convention rooms should be more available/less expensive.  People should not be encouraged to bring adult diapers.  That would get way too gross way too fast.

Yeah, I'm leaving it on that note: full, stinky, possibly dripping adult diapers.
(also heavily used)

OR! To make sure clothes dont get stinky! We could kill two birds with one stone.
Longest Lan Party, and LONGEST NAKED LAN PARTY!

Well if everyone is at there computer, you wont see the junk! Plus I know I wont be looking at other guys junk

OR! To make sure clothes dont get stinky! We could kill two birds with one stone.
Longest Lan Party, and LONGEST NAKED LAN PARTY!

.....

SPECIFIC GUIDELINES PACK
This document acts as a guide to the specific considerations and
undertakings for your potential attempt on the Guinness World
Records
TM
 category and is used in conjunction with the Record
Breakers’ Pack, which outlines the evidence required to prove
your attempt’s success.  This should be read and understood by
all concerned with the record attempt prior to the attempt – this
includes every participant, organiser and witness.
These guidelines are specific to your attempt and must be
followed.  Should any guideline be contravened, your attempt will
be disqualified, without any right of appeal.
Please note that, as detailed in the Agreement Regarding
Record Attempts, these guidelines in no way provide any kind of
safety advice or can be construed as providing any comfort that
the record is free from risk.  Guinness World Records will not
accept responsibility for the safety of participants or bystanders
in any record attempt. It is your sole responsibility to ensure that
all necessary safety precautions are in place and that all
equipment used is suitable and thoroughly checked prior to the
record attempt taking place and in compliance with any and all
local health and safety laws and regulations.

LAN PARTY - ENDURANCE MARATHON
DEFINITION OF RECORD
This record is for the longest LAN party, measured by the duration of the continuous party with
the same participants.
This record is to be attempted by an organisation.
The measurement value is time in days, hours and minutes.
GUIDELINES FOR ‘LAN PARTY – ENDURANCE MARATHON’
1. The event must be in a single location, which does not normally host a
computer network of this size.
2. Each person attending the party must bring their own home computer in order
to count towards the total attendance figure.
3. At least 100 participants must remain at the party and continue to play a
videogame with other participants in the LAN.
GENERAL ‘ENDURANCE’ GUIDELINES
ƒ The name of the organisation, company or person(s) making the attempt must
be given, along with the date and place.
ƒ The event should take place in a public place or in a venue open to public
inspection.
ƒ Two experienced timekeepers (e.g. from a local athletics club) must time the
attempt with stopwatches accurate to 0.01 seconds. If there is any difference
between the two timings, the average should be recorded as the official time.
ƒ No person under the age of 16 may attempt this record.  Persons aged between
16 and 18 must be in possession of a document signed by their parent or legal
guardian, giving them permission to compete. This must be added to the log
book and witnessed before the attempt has started.
ƒ The attempt must be overseen by suitable stewards, who are not witnesses, but
part of the attempt’s support team. The duties of the stewards may include:
a. maintaining log books throughout the attempt;
b. registering of the witnesses;
c. obtaining the signatures and addresses of the witnesses (see below)
ƒ Two independent witnesses must be present at all times throughout the attempt.
The witnesses must also rotate in four hour shifts: any number of witnesses may
participate on the rota. Witnesses must sign the log book at the beginning and
end of each shift confirming the details entered into the log book for the period
during which they are on duty.  No one related to any ‘contestant’ can act as a
witness. No one under 18 years of age may serve as a witness.
ƒ Rest breaks – see ‘LOGBOOK FOR ENDURANCE ATTEMPTS’ section

ADDITIONAL EVIDENCE
¾ We draw your attention to the paragraph above regarding witnesses, as this
applies to all marathons – we require signed statements from every witness that
took part.
¾ Video footage – unfortunately, we do not have the time to watch over 24 hours
of video evidence and so suggest you give us a highlights package.  This must
include: 
o Footage of the start of the attempt
o Before and after each rest break – a clock or timer must be visible on
screen, but not the camcorder’s own time display
o The point at which the record is broken
o The end of the attempt.
o The camera must be focussed on the attempt at all times and preferably
be static.
¾ Logbooks – you must have separate logbooks for the following:
o Witness changeovers, rest breaks and any pertinent observations
regarding the attempt itself (to be filled in by witnesses - see following
section)
o Scoring, game times and substitutions (particularly for sports marathons)
or lists and timings of songs/music (particularly for musical marathons)
¾ Failure to include the required documentation will ultimately delay the outcome
of your claim or lead to its rejection.

LOGBOOK FOR ENDURANCE ATTEMPTS
Rest breaks are the only point where the claimant may stop performing the activity
during the attempt.  They are to be filled in by the witnesses each time the claimant
takes a break and must show the changeover of witnesses.
Rest breaks are the only time the claimant can take a bathroom break or sleep during
the attempt.  They may consume food and drink while the record is in progress, but
this must not disrupt the flow of the attempt.  The following acts as an example of how
to calculate and monitor rest breaks during marathon endurance events.
In simple terms, you are allowed 5 minutes rest for every continuously completed hour
of activity.  These can be accumulated to give, for example, 20 minutes worth of rest
time after 4 full hours of activity.  If you do a shift of 4 hours 30 minutes activity without
stopping, you have still only accumulated 20 minute as only completed hours count.   
Any rest time that has been accumulated can be taken in full or in part at the discretion
of the participant(s) at the appropriate time. Any unused rest time can then be carried
forward to be taken at a future time during the attempt. However any unused rest time
cannot be added to the end of the attempt when it is completed.
The following example has been filled into a copy of the log sheet to show how the
witnesses to the attempt must fill the logbook out.
(1)
If participants play from 12:00 – 16:30, this is four hours thirty minutes worth of
activity and therefore allows up to 20 minutes rest – 4 completed hours multiplied by 5
minutes.
(2)
 The team rests for ten minutes from 16:31 to 16:41 and they can then carry the
other 10 minutes they are entitled to forward for use in the future.
(3)
 The team then play from 16:42 to 18:32, which is one hour 50 minutes and accrues
5 minutes rest for one completed hour of activity.
(4)
 At this time they would be able to take up to 15 minutes of rest (5 accrued from
recent activity plus 10 carried over). Note that the team have only accrued 25 minutes
of rest, although they have actually been playing for 6 hours 20 minutes in total.
Rest breaks are the only point where the claimant may take a bathroom break.  You
may consume food and drink while the record is in progress, but this must not disrupt
the flow of the attempt.
Additionally there is a blank logbook sheet included that you can copy as many times
as you wish for your attempt. We recommend that you use this to ensure that you take
the rest time that you’re entitled to. 
Should you have any questions, please don’t hesitate to contact us.