Before I became a home-owner I got this little solar-powered lantern which also can use AA batteries. I always loved the idea of solar power as it's the cleanest energy around. This one was made for "camping" but I mainly got it to use it for the times when there is no power. And just to see if it was any good or not.
It really does need to be outside to get any real power. I tried to keep it inside just in case it rains cats and dogs. It can get energy through the window but the glass blocks a lot of UV light from getting in so it's always weak.
But at full power it can light a small room with enough light. It's not super-bright but I often use it at night to guide my way through hallways. While all my lights are either CFL or LED, I'd rather use the lantern if I can. As it does nothing to my power bill and is even better for the environment.