I saw this video and it practically melted my brain.

DragonForce - Through the Fire and Flames / Fury of the Storm.... on Guitar Hero. That guy is my hero. (even though its probably a fat asian guy with no life)

Fire n Flames (insane)
http://www.youtube.com/watch?v=wV0qM6-HLuk

Fury of the Storm (even more insane)
http://www.youtube.com/watch?v=_29IFMJNt7s


And possibly the greatest video on youtube I have EVER seen... a giant piece of pizza playing a custom made double-neck guitar doing both players at once:

http://www.youtube.com/watch?v=alY43qMvxM0