A term used to describe massive modification of something to make it standout and look attractive.
The term is derived from the way pimps modify their cars with various colors, lights and other hardware.
Drummer to Pianist: "Damn, your keyboard is totally pimped out! What's all that LED lights and glowing buttons!"
Geek: "I've pimped my computer out - Now it has a transparent side and florescent lamps inside it."
Some Guy: "I'm gonna pimp out my cellular phone by covering it with a 3D skinned panel."