I've been busy lately tinkering on and off and thought readers might be interested in what I've been working on.
I spent a few nights of spare time last week rebuilding my bluetooth ski helmet, which is now working perfectly with a new main board. It's a glove- and snow-friendly conversion of a Motorola S305, retaining nothing but the main PCB, with the earphones and mic broken out to 3.5mm jacks, all buttons broken out to .1" pin headers, a much bigger battery, and an Adafruit USB LiIon/LiPoly charger. I'll post a few pictures soon, and it will get a full shakedown this weekend at Alpine and/or Squaw.
I backed the Printrbot project on Kickstarter a few months ago and received the printed parts in the mail recently, so I've got the 3D printing bug. After raising over 33x of the target funding, its creator Brook Drumm is understandably busy getting promised kits out to other backers. That leaves a lot for me to get together, mainly the hardware, electronics, and hot end, but without an official BOM I'm picking through lots of incomplete lists and RepRap parts wikis. The mechanical design being so much simpler than a Prusa Mendel is what got me interested, and I'm happy working on it when time allows over the next few months. It could be Arduino-driven but that's still up in the air; Sanguinololu electronics are included in the complete kit, so I have a few Pololu A4988 stepper driver boards on the way to play around with.
I did use an Arduino (actually a Boarduino) a few weeks ago to build something for work, but as cool as it is, I can't discuss it here except to say that it's camera-related... of course :)