Ok so you have to have a sense of humor about yourself so here are a few funny things I found in my head.
Again click on the images to get the full picture.

Smiley Brain 
I dont need to say anymore.

The Predator:
Maybe I have an hidden predator in me.

Eyeballs:
Well first off there a funny set of eyes :)

Snake in my head:
Hmm maybe I have a snake in my head, or for fans of Stargate a g'houl (and no i dont know how to spell it).