Some time ago I saw in some catalog the description of the Paris lamp from Zweibrüder. I was immediately fascinated by the elegant design of this LED lamp and the prospect of having one of those acrylic glass lights in my appartment made me order one on the spot. The lamp comes equipped with three high power LEDs (red, green and blue) and three switches in the foot to turn them on and off individually. Using all combinations, one can have the rod glow in 7 different colors, which is nice but gets a bit boring in the long run.
The decision was clear: build a μC circuit that fits in the foot of the lamp and drives the three LEDs according to parameters set by the buttons. I wanted a nice glowing-color-changing-at-different-speeds effect, so I programmed a timer-interrupt driven PWM that can make the three (in fact, it can do 8) LEDs shine at 256 levels of brightness.When the brightness is modulated with a sine-like function at different speed for each LED, we get the desired effect.
Schematic and board layout:   
You can download Postscript files of the PCB and the parts. The C program sports a linear interpolation to make the glowing smoother (if you don't know how to use the avr-gcc environment, read my nixie clock page).
The circuit built into the Paris foot looks like this:

For a dear friend I built a lamp from scratch.

Have fun!