This is pretty cool

[geoboy]

I've seen it before, and yeah it is cool, but a lot of the notes were off. That's probably because it was a live performance. Anyway, there's also another fantastic Mario theme done a cappella by <a href="http://www-scf.usc.edu/~osmosis/music.html">Reverse Osmosis</a>. Scroll down to the song named "Nintendapella" and clink to listen to the demo.