Tim Walker of The Neon Gallery sent this in - it is an LED clock powered by an Arduino Pro Mini. It displays the temperature and humidity in addition to the time. Check it out:
One of our Facebook fans, John, shared a link to this all-transistor clock kit. That's right, this is a kit: 194 Transistors, 566 Diodes, 400 Resistors and 87 Capacitors. The PCB + components is $199 while the PCB alone is $100. For the amount of engineering that went in to this, it seems like a very reasonable price. (Besides, it isn't like I could engineer one of these. It isn't exactly an Arduino + LCD) While you're at his site, be sure to check out his TTL clock, microprocessor clock and calendars too.
If you're thinking about getting on of these, you can view the assembly manual here: http://transistorclock.com/tranmanual.pdf
From the guy who brought us the Verbarius clock comes the Segmentus. (Is anyone else noticing a naming pattern here?) This concept clock was built to address the challenge of creating a digital clock with hands. While clocks have addressed this challenge before, this one brings the usual Art Lebedev polish to the final product. The only thing I want to know is how noisy would this be to operate? With dozens of little motors and mechanical parts, this might not be a clock that you would keep in your bedroom.
One of the members of the Tube Clock Database Facebook Page shared a link to a nixie tube screen saver that he created. I don't have a Windows computer to try it out on but if you've used it, let me know how it goes in the comments.