ioch and nightshade have been playing with a 100W RGB LED pwf bought a long time ago. 

Here’s the LED array:

A transformer which lowers the mains voltage to 40V:

3 LED drivers that switch the red, green and blue LEDs on and off respectively:

The underside of the board:

An Arduino to rule them all. It samples the HSV colour space by setting S=1, V=1, H=random and switching the LED drivers on and off.

The big picture of this pile of hacks. There’s also a cooling fan, powered by a lab power source:

The final result (seizure warning!!!):