The Parallax forum has an interesting supercomputer project based on 11 Parallax Basic Stamp micro-controllers. This might not be a supercomputer based on Wikipedia’s definition, but it’s still an amazing accomplishment.
This is the World’s First talking Basic Stamp Hobby Supercomputer!!! (and the World’s 1st Supercomputer built from hobby microcontrollers) It communicates by English and Chinese voice (EMIC TTS board), lights (21 LEDs), vision, sound (12 speakers), motion (PIR), ports (176), infrared, Vibra Tab Mass detector, accelerometer, temperature chip, ultrasonics [PING)))], LCD Liquid Crystal Display, and a tiny uOLED color monitor. Attachments include a keyboard, 3D space mouse, and other goodies under development.
More about the Basic Stamp supercomputer