Pseudo Music Visualizer (Winamp/WMP/etc)

Okay, so I'm making a platforming game and for some of the backgrounds, I want to create the type of images you'd see in a media player visualization, like Winamp. I don't necessarily care about them moving to the beat of the music, since they're just backgrounds. They only need to give off the illusion that it's a real visualizer.

So what I'm wondering is, what's the best way to render these kind of psychedelic animated patterns? Frame-by-frame animation would be a pain to animate by hand, and it would likely produce too many large files. Should I do it by particle effects? Any good tutorials for achieving that kind of look through Shuriken?

Here's a few samples of the kind of visuals that I'm looking for. Thanks!