Haha, I dig this.
Just rain + ability to tweak thunder. http://www.raining.fm
Really, try this one;
Don't care for the rain. Just here for jazz.
That "jazz" doesn't do it for me at all. Really sounded like some of that cheap stock music you'd get with educational videos. You know. While watching how cows get milked.
Anyway, for anyone who wants more control over what type of rain, thunder, etc:
Nice concept, but it feels like it should have been called EasyListeningAndRain.
The idea is great. The design is awful.