A solar powered alarm clock? Really? Yes, that sounds counter-intuitive, but it's true!
According to the manufacturer, one day's worth of charging will last a whole year, so you don't need to worry about cloudy days or dark bedrooms. It has kind of a 1950's nuclear bomb shelter look to it, but if it really does hold its charge, you could use it almost anywhere without worrying about power outages (including, I guess, a bomb shelter!). And because it is solar powered, i.e. it uses alternative energy, you can consider yourself green as a bonus.