We need an internet based "baby pool" program to take bets on the due date (and a second one for people who prefer to bet against it happening at all). It isn't literally for babies, but that's the closest similar event to this. It will require a db and listing of entrants (who may wind up being in the millions of players, if this catches on) and sorting/searching of the relevant info. It will need to connect to a payment method or a few. (We have paypal installed on one of our sales site domains.)