This is a wonderful way to add an interesting effect to your photos in-camera. This method seems to work best on point-and-shoot cameras, TLRs and camcorders. The kaleidoscope effect is a whole lot more subtle on SLRs, but interesting nevertheless.
Step 1: Materials
If you have some extra time, an empty film canister and a drill or a carpet knife, there's a slightly more advanced way to do this.