Various Valve games (makes me sad, Source and Havok are utter shit)
TES
Free stuff like Warsow, Sauerbraten, ETRacer, ADOM
NOT Dwarf Fortress
I also like to speedrun through various PS{1,2} games.
Of course I've also made various toy games with randomly generated levels and stuff so I can just play those for ohurs on end without ever getting bored or hungry.
Name:
Anonymous2011-05-07 9:58
Perfect Cherry Blossom, Imperishable Nights, Phantasmagoria of Flower View, Mountain of Faith, Subterranean Animism, Undefined Fantastic Object
Ace of Spades
I usually dig a tunnel from the intelligence to the other team and then switch teams and cap it. I cap both team's intel and have a pretty good score for about a hour until they realize what I'm doing and kick me.