The modern DSLR requires so little power that, unaccustomed to the habit, you can forget to charge its battery. But this concept by Weng Jie would solve the problem. It's simply a camera strap with solar paneling.
I know—anyone could have mocked this up, but that doesn't make the idea any less great.
Consider, for instance, the USB-based cellphone solar chargers we've reviewed in the past. Ultimately, they're good in concept but a bit disappointing in practice. Cellphones simple pull too much power too quickly to make solar worthwhile in scenarios beyond emergencies.