Jedi Knight 2: Jedi Outcast. Extremely addictive computer/XBox (/PS2? /Gamecube?) game. Mainly involves controlling a light-saber-wielding jedi and having multiplayer battles with others. Built on the Quake 3 engine. Has much more complexity than trashy first-person shooters such as Counterstrike or Quake 3.
I was oaning this guy DoGLiveD the other day in JK2. He's just a laming n00b. Don't be fooled.