RainBar - Raining on the desktop
I've always been a fan of the various background noise websites like Rainymood. Unfortunately I've never been a fan of having to keep a tab open at all times. Because of this I put together RainBar whilst learning how to make OS X apps last year.
RainBar puts a button on your menubar that plays rain when clicked, you are also able to set the app to launch (but not play!) on login.
You can download RainBar here.
Eventually I'll be launching Rainbar on the App Store but for now, I'll be hosting the code and a compiled copy of the app on Github.
The source code is available for viewing here.