The Long Now Foundation might be an option, but I think that they accept bets only under certain conditions. Otherwise, you can lock the money for a long time

The Long Now Foundation might be an option, but I think that they accept bets only under certain conditions. Otherwise, you can lock the money for a long time with a block chain but you don't have reliable way to insure that the right person will get the money without a third person as a judge and effectively money depositor.