Be the rain. Make sounds.
Move the raindrop with arrow keys. Pause with P. Mute with M. Restart with R. Find fun settings in the pause menu.
For best experience, play fullscreen with volume up.
If you enjoy playing with sound, check out Ueuiiou !
Credit for most audio to Mark DiAngelo, Mike Koenig, battlestar10 and anonymous sources from soundbible.com.