If the current games get a bit old, or a rotation is preferable at some point in the future, I'll suggest a few games to start off, and let others suggest their own (within reason)
Now not all games will be everyone's cup of tea, and Spatry has final say in this. But I'll try to limit this to F2P Linux games.
My suggestions would be:
Team Fortress 2
Dota 2 (only if 10-man games is feasible)
And "No More Room In Hell" is a game that keeps the LDC game night on life support, so why not pick it up here? if it weren't for NMRIH, the LDC game night would have died out. I wonder if pdq would let those of us here going for game night use the LDC NMRIH servers...