If you enjoy listening to music that reminds you of living inside of a beehive, with visual effects to go along with it, then this is a great place to start. As seen in the video embedded below, it can produce what can very accurately be described as droning music, which the 64-LED (8×8) display really highlights. All joking aside this is a very cool way to couple video generation with audio synthesis.
Videodrone produces audio via two voltage-controlled oscillators (VCOs), two triangle wave low-frequency oscillators (LFOs), and various other sound modification bits. Video is generated by the instantaneous output voltage of the VCOs in a similar manner to how an analog TV works. The 8×8 LED matrix scans from left to right, and top line to bottom line, varying brightness based the VCOs. Turn the clock up fast enough and patterns corresponding with the audio synthesis clocks emerges.
The board is designed with circuit benders in mind. It includes video input for the display, so it can be driven with any line level audio source. And the video tutorial starts off with an example of some off-board additions to slow the clock down to a crawl.
Coppertraces put together a Videodrone synth kit, but has also published documentation for this device, including a schematic, bill of materials, and build notes.