I'm actually thinking of something like this:
http://www.thinkgeek.com/product/eb7b/#tabs
an emergency power source for phones, ipods, and so on. My kids have a lamentable tendency to not keep their phones charged up except at night. We've got a small one, that works to recharge my son's phone about half way (or maybe a little more), and I've got a charger that runs on two AA batteries, but I don't know how much that small amount can do.
I've investigated solar rechargers, but I'm not convinced we'd have a good way to use it in cloudy Michigan. For longer outages, we've got a gas-powered generator (but that assumes we can get gas for it) - this would be just for more short-term emergencies. (maybe give the kids one to keep in their car)