Tweet a Sound is a small application that lets you design a simple sound and send it over Twitter. You download the application from the Sound + Design website, and you can start tweaking your sound. Once you're happy with the result you can tweet it, which sends an unreadable tweet to your account. It's just a series of numbers prefixed with #tas:
It would be nice to have Twitter integrated in the program so you can receive sounds directly. This is not possible though. You'll have to copy paste the code into the program in order to play the sound.
Now why would you want to do this?