Chalk this one up as one of the more unique accessories for your iPad and other slate-style tablets: a stand in the shape of a whale's tail.
Officially called the Octa Vaccum Dock + WhaleTail Stand, it goes by Tablet Tail for short and literally suctions onto the back of your device. It can prop your tablet up in both a horizontal or vertical position, and the tail is removable from the vacuum dock, which allows you to break down for transport in the included cloth carry case.
Though somewhat pricey at $49.95, the accessory is fairly lightweight yet sturdy and has a nifty design. To adhere it to your device, you simply press it gently up to a flat clean surface, and press the protruding button on the dock to suck out all the air and create a vacuum seal. It does not help to press the suction cup hard up against the surface. Rather, you just want to hold it up against the surface, and as the air gets pulled out, the suction cup will work its way down until it's flush against it.
The key is to have a flat, "nonporous" surface to work with. That means that you can use this if you have a back case on your iPad so long as it's smooth (I tried it with a few different back cases and it worked fine). You also need to make sure the suction cup stays clean and doesn't get punctured.
Octa says, "Performance will vary with the cleanliness and condition of both your electronic device and this accessory."