RGB LED matrix in a colander hat.
A boombox briefcase with some extra pazazz.
X-ray slide lightbox converted to display equiliser bars using MSGEQ7 audio processor and WS2803 LED drivers. Also contains an oscilloscope built from old portable CRT TV.
LED matrix panels built with 4' x 2' peg boards. Matrices are controlled by PIC18F4550 microcontrollers with additional hardware for audio processing and RS232 input.