Below we have put together some helpful information on how to host a lan party. Lan Parties range in size greatly from just a few friends to thousands of gamers coming together at convention centers. While most of us could probably never afford the later, we'll focus on the small to mid size parties. For a list of Lan Games played at lan parties, check out our discussion on them here: Lan Party Games.
Small (4-16 People)
Usually for small lan parties you can probably squeeze up to 16, maybe 20 people into your own home and see how it works. One crucial item to remember is that most gamers that play often usually have decent rigs that suck a lot of power so you'll need to separate your friends into separate rooms to offset the load or you'll overload a circuit. Yipes!
Small-Medium (16-50 People)
A lan of this size gets a little more tricky since you have friends that have brought friends plus several people you don't know as well. You should follow the same guidelines as above but you'll obviously need more room. So unless you have a mansion your best bet is to rent out a small warehouse, hotel meeting area or some kind of cheap office space. Since you won't have to worry about power as much since the facality will most likely have it covered (Ask to make sure), your main concern is those that have come to this lan event. Keep a close eye on everyone attending and have friends help with this if possible. It's always better to be safe than sorry if you return to frag some people and you see your rig missing! :O
Medium (50-200 People)
Once you have this many people coming to a lan event you might be hosting, it would be a good thing to start charging since you're probably paying an arm and a leg for the space and power consumption, so unless you have sponsers, it's usually a good idea to charge at least $10 a head to recoupe costs.
Resourceful Links for finding what you need:
Craigslist.org – We suggest looking here for renting space.
NewEgg – Networking Equipment that you "will" need!