Thought this was a good find. Someone was playing around with Wave Race: BS and they found a hidden code:
The racing commentary turns into a sarcastic guy who insults you at every turn and your turbo boost is replaced with a girl going "Meow meow!". It's funny how this stayed hidden for so long.Go to Options and Audio Settings.
There’s a waveform display at the bottom that changes if you press the Z Button—tap Z until the waveform looks like vertically rising fog.
On the D-Pad, press Up, Up, Down, Down, Left, Right, Left, Right, A, X, Z. You’ll hear an audio cue if you did it right.
Back out to the front end.
Start a race. Pick the first guy.
Video example:
http://www.youtube.com/watch?v=vNDOcyEGhoQ