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.
Psychonauts
Delta Force Task Force Dagger
WTC mod for IV
Half-Life Visitors
Frontline Defense 2
Rocket Pack for Pocket Tanks Deluxe
EpicBot
Starport GE
Tick The
Chicken Chase
Back to the Future: Hill Valley
Spec Ops: The Line
Zula Game
Kane and Lynch Dead Men
Mega Games 6in Vol 3
Alone in the Dark
DARK VOID
Galaxy Battles
Team Fortress Classic
Phoenix Assault
Zombie Smashers X2
Out Of The World
Carmageddon Mod
STAR WARS™ Battlefront™
Teeworlds
DooM Legacy
Piercing Blow
Tread Marks
Funny Hell
Discover FDM
Add-on support
You can get add-ons that download files/video from arbitrary websites.