This is kind of fun to do. While on Double-Decker battle feild, go to the very top. Without stopping or slowing down, jump off the top floor to where you just started the game. Before hitting the ground, hold the R, A, B, Z, and press the stick all the way to the right. If you did this correctly, your character should sink into the ground a little while doing a doughnut. NOTE: this does not always work, keep trying. Also, heavier characters work better.
Added by: Rangerman Nov 7th 2007, ID#6151