I think for our Summer Event it is not as important to have a specific set of games that people will be playing, as there are so many people it is inevitable that someone will be playing what you are. And with the internal IRC server setup it is easy to find like-minded people to play with.
For our Winter LAN I think it might be more important to have the same set of games. With the smaller event there will be less variety of games.
Here is what I would focus on (based on past small LAN experience and current games):
Flatout 2/3 - just plain fun to fill the void between other more established "serious" games
Trackmania - same reason
CS:S/CS1.6 - pick your flavour as I am sure both will make an appearance
WCIII/DOTA - yes I know they are not the same thing
Network Hearts - srsly
and the most important of all games (as this is what the FP staff play) - ET:QW
If you have even a few of those you will be set. I'm sure if you look hard enough you will be able to find the games you are missing from the list and be able to join in the festivities.