Philippe Chrétien built an interactive RGB lamp. The lamp has no switch and no dimmer, it's entirely controlled with radio frequency identification (RFID) tags. The RFID reader is hidden in the lamp body and the RFID tags are embedded in colored wooden disks.
You can change the color of the lamp by placing a colored disc into the circular recess in front of the lamp body. When no disc is placed in the receptacle, the lamp changes color randomly. Place the white disc to produce a white light and the black disk to turn off the lamp. You can also turn the lamp into a stroboscope or produce other special effects by combining different sequences of colors.