We've just happened upon a new site called ChallengePost, where entrepreneurs can post the projects they're working on to seek funding and support.  Potential investors can pledge a few bucks, and the return on investment can range from a simple reimbursement to a percentage of the profits to a number of creative prizes.

From the site:

"A new iPhone app that points me toward deals at my favorite retailer; a cheap, small solar-powered generator; a better way to teach kids math. ChallengePost allows you to create and join challenges to accomplish goals. It also allows organizations to sponsor competitions of the same variety.

Once a challenge is created, other people can JOIN the challenge and pledge money or simply appreciation. Those incentives, which are payable only if a challenge is solved, encourage others to solve a problem and earn their rewards.

Solving a problem or getting a wish granted always needs a first step. Get started today with ChallengePost."

An example of a current challenge: a 2010 FIFA World Cup Realtime Dashboard:

You can also use ChallengePost to create challenges for others to solve. Thompson Reuters is using ChallengePost to seek great mobile applications for financial professionals: