Via kottke.org:
Passage, a tiny game that takes 5 minutes or an entire lifetime to play. It’s much better if you play it once and then read the creator’s statement. I didn’t know a game (and such a tiny one at that) could be so poignant.
I’ll second that. Please check this out, and definitely make sure you play the game once before you read the creator’s statement. You’ll be glad you did. I must admit, this one got me a little