buran electrix‘s Lunchbeat, a “simple groovemachine with 8 step sequencer and four 1bit sounds” via Create Digital Music:

LUNCHBEAT is a 1-bit groovebox, making impossibly-dirty digital sounds, with a built-in step sequencer. While we await a proper DIY kit, it’s an ideal learning project: it’s nice and simple, has a low part count, everything you need as far as specs is available free to create your own, and it’s a good way to work out the basics of digital sound and sequencing.

Lunchbeat is also hackable:

ISP6pin – hacker’s gate to unit’s microcontroller. Tweak the sound algorithms. Tweak the sequencer. Change unit’s purpose completely. Use the fact that Lunchbeat is the same thing as Arduino with 6 buttons, 5 pots, 8 LEDs on SPI shift register and 3-bit digital to analog converter. You can run Arduino sketches on it. From here it is up to you and your fantasy.

See more at buranelectrix.com!