Go to any level in Freeskate mode. Enter high score mode. Press B while walking to let your board go, and while it's leaving your hand, go to end high score run. When it restarts, your skater will skate right off his board, but still be skating. You are now skating with no skateboard. Once you walk, he will walk as if he never had a board in his hand. The board will appear again if you fall in water.