The Etch-A-SDR is a Etch-A-Sketch and SDR all in one! Built with an Odroid C1, Teensy 3.1 and RTL-SDR.
Demo: https://www.youtube.com/watch?v=1YYz0kW67oU
Presentation at Cyberspectrum SDR Meetup: https://www.youtube.com/watch?v=tG70c3Zadek
Slides from Cyberspectrum Presentation: https://github.com/devnulling/etch-a-sdr-presentation