I had some great fun with the PixelCompetition on the rC3. Everyone could send some TCP packets with coordinates and colors that will end up in a video stream.
A competition on the canvas: You need to be faster in sending the packets than the others or find an unused corner on the canvas for yourself. I ended up using my Raspberry to set the "Chaos-/Hasi-Siegen-Palme" in the upper right corner.
Here are some of the python scripts I used and also some screenshots.