I added some LEDs on the Pitchou and just wanted to be able to switch them on/off using the radio. I could have bought something, but it would probably have been expensive, would have taken a long time to arrive, wouldn't be customizable, … So I took an Attiny85 (smd version) and made a really small board that takes a servo PWM input, and can toggle three outputs. Cheap, fun, useful, …
(print at 600DPI)
Here's a panelized version, with six of them: Panel
Because I didn't want to bother with ICSP, I flashed a http://jtxp.org/tech/tinysafeboot_en.htmbootloader before soldering the Attiny on the board. I wanted to use the same bootloader used by the SimonK firmware but couldn't find enuough documentation to easily port it… Maybe later.