This game is really fun. Very unique indie game. You can travel back in time all you want pretty much in case you want to do something different or in case you die.
http://store.steampowered.com/app/26800/
Edit: For the next 48 hours this game is also available on the Apple Mac store for .99 cents.
http://itunes.apple.com/us/app/braid/id411902645?mt=12