I've been toying with the idea of using physics simulations to generate audio.
First, imagine a audio in a circular loop, as on a record player. As the needle moves clockwise, the music plays. If the needle moves counter-clockwise, the music is played backwards. The faster the needle moves, the faster (and higher pitched) the sound.
Now, model the chaotic motion of a double pendulum, and use that as the needle that is driving the music:
It can also be interesting to use the data directly. Take a physics model of a double pendulum, and record the height (y) of the longer leg over time. Then, interpret that data as raw audio samples and play it!