Klein Bottle

A Klein bottle is an interesting thingy. It is a three-dimensional object with one surface and no edges. You say, "So what, it's just like a sphere." Wrong. A sphere has two surfaces, one on the outside and one on the inside. Therefore, a Klein bottle's surfaces run into each other. It's called a bottle because it's usually depicted all bottley, seeing as it contains itself. Naturally, it's theoretic, as such a thing would have to pass through itself, making it impossible to construct in real life (or at least our dimension). Didn't stop these guys from trying.

At KleinBottle.com, your impossible dream becomes a semi-reality. Though not true Klein bottles, they still kick ass. So buy one. I told 'em you would. Don't make me a liar.