1 ETH = 500USD ** 0.5 ETH smart contract giveaway ** Two weeks to guess!
TLDR below. See the Github repo for detailed information.
I've deployed a smart contract loaded with 0.5 ETH. The address that guesses closest to when ETH hits 500 USD wins the bulk of it. There are 14 days of guessing, starting as of block 6298999. Once we hit 500 USD, a secondary prize is immediately up for grabs (10% of balance, an incentive to call a certain function asap). Then a 7 day nomination period begins (for those who think their guesses are competitive), after which a winner can be declared to receive the remaining balance. Feedback welcome, and I imagine there are more elegant ways to do some of this but I've given the contract logic and game theory a lot of thought and just needed to pull the trigger on it with some real ETH on the line.
My small gift to the crypto community, enjoy and good luck!