Rock the block, don't stop.

This chick is awesome with an electric violin

So is this guy here.
[video=youtube;-hTciGp0c_U]http://www.youtube.com/watch?v=-hTciGp0c_U[/video]
Seriously though, that girl is awesome on the electric violin.

Linked some of these on a few Funhouse threads a long time ago: wouldn't hurt to post these again-

 Legendary Multitasking Guy

U.N. Owen was Her
[video=youtube;qTU84uwyN5w]http://www.youtube.com/watch?v=qTU84uwyN5w[/video]

Cruel Angel's Thesis+Fly me to the Moon
[video=youtube;BR6WZfz1tas]http://www.youtube.com/watch?v=BR6WZfz1tas[/video]

Tank
[video=youtube;5Cgs51_XBzA]http://www.youtube.com/watch?v=5Cgs51_XBzA[/video]

 That fellow with a horse mask from Nico Nico Douga.

Haruhi Medley:
[video=youtube;yXvK7GhSQ5Q]http://www.youtube.com/watch?v=yXvK7GhSQ5Q[/video]

Medley of Stuff
[video=youtube;GdWk83kESC4]http://www.youtube.com/watch?v=GdWk83kESC4[/video]

EDIT: Beaten by Spidey while I was working on this list

Wish I knew what the heck his name is.
[spoiler=Don't know this dude's name either, but he plays awesome Pokemanz stuff]
Elite 4 Champion theme for R/G/B/Y
[video=youtube;hAiKRyoVG18]http://www.youtube.com/watch?v=hAiKRyoVG18[/video]

Gym Battle theme
[video=youtube;_E8dGtCh8cA]http://www.youtube.com/watch?v=_E8dGtCh8cA[/video]
[/spoiler]

Finally, the rest in here:

 Other

[video=youtube;uRv8gnBMiWM]http://www.youtube.com/watch?v=uRv8gnBMiWM[/video]
[video=youtube;DtzpGKadgew]http://www.youtube.com/watch?v=DtzpGKadgew[/video]