Yes, I love google but (as I said in Software forum):
One "gotcha" is that they get the rights to use all of the entries as they see fit (including selling the design) without further payment, not just the winning entry:
<< With regard to an entry you submit as part of the Contest, you grant Google a worldwide, perpetual, fully paid-up, non-exclusive license to make, sell, or use the technology related thereto, including but not limited to the software, algorithms, techniques, concepts, etc., associated with the entry. >>
kind of annoying if you're a runner-up and get $0 but Google still uses your work.