It's definitely not the most efficient way to get a clock on your wall (or the cheapest), but if you're interested in tinkering with an Arduino, this laser wall clock definitely fits the bill.
If you dig DIY clocks or you just think lasers are cool, this is the kind of project that you might want to try, especially if you're getting started with Arduino projects. You'll need an Arduino, of course, and you'll also need a pair of laser pointers, a few servos and motors to make the lasers move as time passes, and of course the IKEA BLANDA salad bowl, available for six bucks, which will serve as the housing for all of the gear.
The wiring diagram and some more shots of the clock are available at Zouliv's blog, where he explains the process of assembling the whole thing. It's not terribly detailed, so you'll have to fill in the gaps, but if you're interested in building one yourself, it shouldn't be too difficult once you get started. The Arduino can be made to keep its own time, although Zouliv connected his to a computer over USB (you can see the cable) to keep accurate time. What do you think, a good starter project, or modern design gone horribly wrong? Share your thoughts in the comments below.