I participated in a competition at animationforum.net. The task was to create a dance animation for pre selected music track.
You can watch the finished animation here

Here are some earlier versions of the file if you're intrested in seeing the whole process of it:

1: quick thumbnails and timing for the animation

2: rough keyframes. Pass1

3: rough keyframes. Pass2

4: cleaned up the background

5: cleaned up the keys:

6: Finished