Monster Hunter Freedom

Probably Super Smash Bros Brawl.

oblivion, that game reels you in.

Most recently it's been Oblivion(well over 200 hours) and MLB 08's Road to the Show feature.
All time, I'm with Calamity, I spent more time with Tetris than any game since. I seriously doubt any game will ever come close.
Honorable mention has to go to Solitare and Minesweeper at work.

I've already been warned by a friend, though, that Disgaea 3 will be a legendary timesuck. So I'm looking forward to that, albeit with some trepidation.

Currently Assassins Creed, Trying to fully complete every Memory Block


Ages Ago Probably:
Destroy All Humans!
Dead Rising
The Sims

 That's cheating!!!!!

 actually I do it too

WoW would of been, but I played mmorpgs before and didn't let myself get addicted. I quit when my druid got to lvl 22 or so. For me the most addicting game was probably Rose Online (PC) or Fire Emblem (GBA)

duke nukem 64 multiplayer. I don't know how many hours I spend playing this

Animal Crossing (GCN)

Animal Crossing Wild World for DS [I used the tactic described by Pichu]

Star Wars Battlefront and Battlefront 2 [I got legendary in everything except rockets and sniper]

GTA: San Andreas [over 600 hours on multiple files, at least]

Halo Custom Edition [over 120 hours of multiplayer]