Yeah, I know it's nothing like the real thing but it's free and it's raining and you should be working...
About a 12 Mb download but quite fun if you're into this sort of nonsense

http://www.hammerware.cz/aquadelic_bg-setup.exe

Sorry I don't provide tech support for this - just save the file to your drive and run it - it will set itself up. If it runs a bit 'choppy' run the setup-exe file in the install directory to tweak the details levels and it'll run faster (you'll probably want to turn the slightly annoying music down while you're there as well...)

Enjoy,

R