Open source hardware makes me happy. Open source has been around in the software world for a long time, but it's still fairly new in the hardware dimension. I think 2009 might just be the year that OSHW reached critical mass. Certainly, the Arduino is now everywhere, but there are other great opens source hardware projects getting some coverage too. My favorite is still the Beagleboard - a super powerful ARM Cortext-A8 based computer in an open source 3" x 3" form factor.
Gerald Coley, of Texas Instruments wrote a great article in EDN Magazine last year. His work is a finalist for the best contributed article category in EDNs Innovation Awards. Check it out. It's a great read.
Curse you, Red Baron!