Ben Heck, king of the video game modders, has gone and made a shirt based on the game Portal. It has a portal on the front that lets you see right through to what's going on on the other side. It's pretty clever!
The shirt essentially consists of an LCD panel on the front, a camera on the back and a battery pack connecting the two. With the camera pointing backwards, it shows whatever is back there on the screen on the chest. This gives the illusion that there's a hole going right through you.
It's not for sale, but he is giving the shirt away in a contest if you're interested.