Amazing Timewaster: LineFlyer.org
OK, let me see if I can keep this post simple. You've seen the now-classic falling sand game, not to mention its upstart little brother, pyro sand (where you can do some really cool things by making the sand act like gunpowder!), but... add to this, Line Rider, where this little guy goes down a line on his sled. FUN. So... anyway, LineRider.org saves little movies people have made of him doing his thing! Even one that reminds me of a cat playing with a mouse! They're fun! And even brilliant when it all finally JUMPS THE SHARK.