As Zos mentioned, the original Half Life provides great variety. It also has very low specs. I am a firefighter, and we set up a lan here at the station. Half Life has provided us with years of laughs. We all brought in rigs of various specs; it works well on all. If you lack the 3d horsepower, you can run it fine in software mode. Team Fortress, Day of Defeat, and Deathmatch just to name a few of the modes and mods. You can also host the game on one of the clients rigs, time limits can also be set. This game is still being played at lunch time here at the Danvers Fire Dept.