Mine would have to be the X-COM series. That game had some much depth and kept me playing for hours during my college years.

 

I would say Half-Life. Changed the entire FPS landscape.

 

Super mario kart with 4 people took up alot of drunk nights

 

Duplicate bridge.

 

NBA 2K series. GT2.

 

Hide the salami.

 

It's a tie.

-Metal Gear Solid
Because it introduced an entirely new concept to gaming, as well as having one of the deepest stories of a game to date at the time of its release.

-Final Fantasy 7
The most complex Final Fantasy, EVER. Hands down NOTHING since has matched it for length, complexity, and utter story. Final Fantasy 1 is my fave FF, and FF X-2 is my current addiction, but FF 7 is the only Final Fantasy that has EVER taken me completely into its world, so much so that I lose track of time entirely playing that game.

 

Hahahaha. You beat me to it! That's my favorite game as well.

 

"Smoke the bong" and "Street Fighter II", in that order.

 

Chess.............Person to person not against a computer.