I've taken to playing Narbascular Drop, after I heard the news about Portal. The graphics are absolutely hideous, but the concept is great (despite the fact that it's a student project, more or less).
City Of Heroes and City Of Villians!!!
I tried to play Legend Of Zelda: Ocarin Of Time, but when I got to the water temple, I decided to not play it anymore. One wrong move there, you have to restart the entire game.