I just saw this for the first time and thought it was funny as hell.It's Alanis doing a parody of the Black Eyed Peas song "My Humps".I don't know if you've seen it,but it's worth a look if you haven't.Even as a parody,Alanis still sings it beautifully.
Here's the Black Eyed Peas version:
http://www.youtube.com/watch?v=iEe_eraFWWs

And Alanis' parody version:

http://www.youtube.com/watch?v=pRmYfVCH2UA