This Lomography Ringflash attaches to the outside of your lens, and its four lighting elements each deliver a different color to your subject. You can use it as a single color ring flash, too, but its makers encourage you to get up close to your subject and flash a picture that has four different kinds of lighting in the same frame. Powered by two AA batteries, it fires via an external hot shoe or its own built-in slave trigger. Might be fun for some trippy looking effects. But that's not all it can do.
The Ringflash was originally invented for tight close-ups of bugs, small objects and still life scenes, because when you get that close, conventional flash heads tend to unevenly light the scene. But this Ringflash lets you use its multi-color ring for multi-colored shadows, use a solid colored gel rings, gel filters and lots of other techniques. The downside is that you must use this Ringflash with special Lomographic cameras, but you can also get those at reasonable prices. It's unclear if you can adapt this Ringflash unit for typical DSLRs.
What the heck is Lomography, anyway? it's almost a way of life for a lot of photographers, and it started with a certain kind of camera that originated in Russia, and eventually turned into a free-form way of taking pictures, often involving fisheye lenses. In fact, the Lomographic Society has its own list of ten rules that it suggests you follow:
1. Take your LOMO everywhere you go and whenever you go.
2. Use it any time —day or night.
3. Lomography is not an interference in your life, but a part of it.
4. Shoot from the hip.
5. Approach the objects of your lomographic desire as close as possible.
6. Don't think.
7. Be fast.
8. You don't have to know beforehand what you've captured on film.
9. You don't have to know afterwards, either.
10. Don't worry about the rules.