ThinkGeek has all sorts of epic geeky clothing and gadgets. The company often combines the geeky clothing with some sort of useful feature like a shirt that has a guitar you can really play.
The latest shirt from ThinkGeek is the BeerBot Bottle Opening Shirt. The thing is offered for about $20 and is in small to XXL. The front of the shirt has a screen-printed robot that is in the shape of a beer bottle, but reminds me a lot of Bender.