Action games
If you don't play games that much, there is a big chance you have played an action game, e.g. a shooter, at some point. This category is full of games that won't let you get bored.
Wreckage
Naev
Rivals Evolution
Breaking Point
C&C 3: The Forgotten
Needles
Gladiators Online
Arbarlith
Out of Hell
DevastationZone Troopers
Westward Value Pack
Jagged Alliance 2 Wildfire
Talmits Adventure
FunnyGames - Pocket Fighter Nova
Spandex Force - Superhero U
Little Hero
Lost Heaven Multiplayer
BrickQuest 2
D-Race 2 New Challenge
Atomic Tanks
Alien Apocalypse
Gothic Multiplayer
Hawken
XTCS Counter-Strike Final
Fear the Beard
The Scourge Project
StarSonata
Discover FDM
Add-on support
You can get add-ons that download files/video from arbitrary websites.