Rap about how great tetris is with the tetris theme song in the background. You can add in percussion if you want.
I think you should write a song about a man ordering a burrito and being extremely intimidated by the size of it. The music should be Celtic techno, or any other blend of two genres that would not be caught eating a burrito together.
(both of those resulted in actual songs, which you can download for free! (the last link has nothing to do with "Songs To Wear Pants To", but you might want to check it out anyways...)