Innocentive challenges

Checkout this web site. Companies/people post problems and will pay for an innovative idea (5k+). i.e. Fixing design issues with a solar power lamp, ideas for cleaning oil spills or improving the design of a third world water pump.
It's a great way to flex your mind and is the perfect 'on the side' project that you can work at your leisure. Why not submit a five page report? I recommend simplicity in the design/implementation.

www.innocentive.com