[Note my very professional setup.]
Bascally, all you do is put some oil and water in a clear dish, hover it over something colorful, and take some macro photos of the circles and designs that show up. It's nothing magical when you consider the mechanics, but I really liked the end result.
I tried different items to add color. Beach towels, blankets and pillowcases. This Care Bear pillowcase provided the most variety and color.
I may try this again sometime! You should give it a try--many point-and-shoot cameras have a decent macro setting, and you don't necessarily need a macro lens anyway. (Although it helps.)
This evening I'm going to take a walk and try to get back in the habit of evening walks with audiobooks, because I enjoyed it so much last spring. What have you been doing this weekend?