A game to play all night long

I'm also late to the party but if you like Civ then check out Europa Universalis 3.

Get ScummVM and play old point and click adventure games like full throttle.

Skyrim is the easy answer. I usually get wrapped up in story games though, so try Borderlands.

Alan Wake, with its creppy setting and seductive story.

trials evolution. alllll niiiiight baby.

i would say thief but you don't have windows. its a stealth game that if you get into is creepy and hilarious with dark humorous. It runs on the quake 2 engin so its old graphics but its really fun if you like that type of game.

The Witcher. Or Witcher 2.

Minecraft, Terraria, Civilization, N-game. All of which are free or cheap.

Civilization V (or IV if you can handle the inferior graphics)

That game will let you forget about time for 10+ hours.