Colorsplash flash by Lomography

For only $35, you can buy this flash and add some really wild color to your images. Here are some examples from a fellow flickr user in the flickr d200 users group.

From Lomography's site:

A patented colorwheel system puts several colored flash filters at your finger tips for instant selection; with additional filters included to exchange within the wheel. Using a variety of techniques, the Colorsplash Flash will vigorously slap a burst of color onto your glowing long exposures, deer-caught-in-headlights instant shots, or bright high-contrast daytime images. Play with different perspectives, color tones, exposure times, and light situations for an endless variety of gorgeous outcomes.

Also, they can be bought on eBay for slightly cheaper.

Apparently the Colorsplash works with the standard hot shoe on most cameras.