You have got to check this out!!! Incredibox is the single most amazing website I have ever come across!
At first you look at it and think "what the hell... how does this work?" but it's very easy and very addicive.
You can drag all sorts of sounds into the little dudes above. They can beatbox, do instruments and sing.
It's just the one song, but you yourself can mold it into a tune with variety by changing the variables around. It even has special effects that you can earn and they really change up the song. Plus you get the above, and awesome, graphics as well.
Apparently there's going to be a new and improved version. I really can't imagine how it can be any better, since it's abslutely perfect as is, but nevertheless I'm exciting to see how it'll turn out.