http://www.darpa.mil/urbanchallenge
NASA does too, but contractor-corruption has gotten in the way:
Can you believe what the pork-barrelers are doing to the NASA-funded competitive prizes program?
http://thomas.loc.gov/cgi-bin/cpquery/?&dbname=cp109&sid=cp109s0tv8&refer=&r_n=sr280.109&item=&sel=TOC_385521&
states that:
"The Committee does not provide any funding in fiscal year 2007 for the Centennial Challenges program. Funding provided in previous fiscal years for this program is sufficient for NASA to run a prize based competition, as well as to verify that NASA will see tangential benefits from running such a program. Providing additional funds to a program based on prizes only creates a pot of unused funds while other aspects of NASA's mission are being cut or delayed due to a lack of funds."
Discussed here:
http://www.spacepolitics.com/archives/001028.html
and more generally here: http://www.spaceprojects.com/prizes
space prizes ping
I'd personally prefer a simple, low 10 per cent flat tax rate on corporations in this country, and they could spend the money on whatever energy form they please. I would give them a tax break if they stay away from Middle Eastern energy imports, however.