For those looking to be more Eco friendly and eliminate the need to buy batteries or plugging in an alarm clock, you will want to check out the Bedol Water Powered Alarm Clock. The Bedol Water Clock uses ions in ordinary tap water to power the clock. Powering your clock is as simple as filling it up from the tap, in 6 months or so when ionization is low, and the clocks LED display dims just dump the water out and refill and your back in business.
The price is right on this device at $26.00 and can be picked up at bedol.com they come in a variety of styles and colors.
Note: This device drove a nice science discussion here as my kids spent some time online figuring it out. I guess what they teach in science class in schools these days is not what it used to be.