Thanks to the awesome mooRainbow script, by Djamil Legato. Powered by MooTools.
[side-note: If you web jockeys out there don’t know it already, MooTools is glorious. We’ve been using it at my company for almost a year and it seems like everyday we find more reasons why it is amazing. Little effects things like this are nice (and fun), but the real power of MooTools hits home when you’re working on a big project and you realize that it’s amazing flexibility and modularity actually make your job appreciably easier. As far as Javascript libraries go, it’s just so nice to work with. The learning curve might be a tiny bit steeper than the others, but the payoffs are worth it. And their documentation is exhaustive.]