Ashoka, through its Changemakers program, is sponsoring a new competition, How to Provide Affordable Housing. There's still almost three weeks left for entries, but already they have 20 strong ideas, including one from our own Vinay, the hexayurt.

Competitions and prizes are an excellent way to spur innovation in the public interest, and while this one doesn't have the cachet of, say, an open source design initiative, it's still worth checking out.