Apparently mine, based on the number of upvotes my Show HN is getting right now ;)
Edit: Maybe that came off as rude, but I really don't get the idea. You pay somebody for something you want to see done? What?
You basically can crowdfund your own X-Prizes.
A group of genetic engineers someplace in the world notice that me and my troop have collectively pledged, say $500k, and the genetic engineers actually spend some time and make such a flower. They send us a video, and we trust they've built it. We get flowers, and they get the money.
Am I right?