I have just ordered this seven-piece reconfigurable Tetris light set, which automatically turns on when all the pieces are stacked together. I bet it sucks; if it does, I’m going to go right ahead and make my own 6ft tall version out of plexiglass squares and LED lamps.
Tetris Constructable Light
UPDATE: Amazon is sold out, but if you’re in the EU, Firebox has them in stock!