Many, many power strips, and at least one good flashlight. There were quite a few times that we'd have too many machines on the same circuit, and just pop breakers left and right. Try to get one person in charge of music as well. The fewer sets of speakers you have in the room, the better you can hear obscenities
What about having a go at ET:QW? Excellent fun! Also, you just need one copy of it for LAN as long as you install it on all the PCs And depending on numbers/how many have the game themselves - L4D? RTS can be fun, but generally they take longer to play and when you have a wide range of games you wanna play you tend not to stick to many of them in - FPS forms the main bulk of the LAN games. Depends on how long you guys are playing for and general consensus - whenever my bros and cousins get together no-one feels like playing an RTS. (except me ) If you want more freebie games then the mods for HL2 are quite good - like Zombie Panic and Synergy and there are a few others. Battlefield 2 is also good for some laughs.
I've got the music all worked out. I have a music server hooked up to my stereo which I have speakers hooked up in both rooms. I do have a copy of ET:QW sitting down here that I purchased for $4. Might give that a try. We usually end up playing a mix of L4D, CS:S, TF2, GMOD, and Synergy. I play Defcon by myself or online usually, with people that want to spend time in thinking out a strategy. Can't, unless I have a projector that's exactly like it. The blue layer/pixels are broke and can't be fixed. Whats next? An Amp? Or a stereo? Shegue Shuffle by RS-232. I was looking through the audioswap function on youtube and thought rs-232 would be fitting. No problem, hopefully I inspired some people. And for those wondering about the powersupply Yeah, dumb I know. But it was fun, and I know I won't be doing it again. If only I had a tripod that time.
