The Mars Volta is an amazing experimental band. Apparently they won a grammy too. I'd call them a latin version of pink floyd. They are quite awesome and really trippy.
Also a lot of their songs are 12-13 minutes long.
I couldn't find and good versions of the long versions of the songs, but you get the gist.
i have a totally post modern tattoo of a scalene triangle.
<DeadorK> fair maiden
<DeadorK> if the cum is going to be in your mouth
<DeadorK> it shall be in mine as well