Google is putting up $30MM of their own money as a prize. This is surely not just a tax write-off or something charitable. Surely this is an investment where they are going to get more monetary value of this in the long run then they're putting up, right?
Autonomous swarms of robots which process lunar soil to build more copies of themselves. The only problem is the prototypes cost <Voice name="DrEvil">100 trillion dollars</Voice>.