Line Rider
Check out this stupidly addicting 'game' of sorts called Line Rider. The game is simple, you can draw 'paint style' a crazy line on a blank canvas; but there is this 'play' button on top. When you press play, a little animated sledding dude gets on a sled and rides your line. It seems kinda hard actually.
Once you've gotten the hang of it, try looking at this Line Rider masterpiece that someone took the time to make. More proof that some people just have too much time on their hands and should be spending that time more wisely (i.e. use that time to find geocaches, etc).
Source:Alejandro, Thanks! (orignal: deviantart.com)