http://nyan.cat/

How much can you listen before your head asplodes? I've reached.... 700 seconds and my head already hurts.

And whatever you do, RESIST THE TEMPTATION TO SING WITH IT!

WARNING:
Nyan cat can cause seisures, headaches, addictance, and madness. (Not sparta)
Singing with the nyan cat will most surely cause your mouth to hurt and, same as before, madness. (Still not sparta). Warning , it is VERY HARD not to sing with it.
And incase the nyan cat poops skittles, do not eat them, they can cause puking rainbows, more madness, heavy seisures and headaches, hallucinations, addictance and SPARTAAAAAAAAAAAAAAAAA!