For example I could put a wager up that I don't think Woman in Black 2 will top $30 million domestically and specify the 2:1 odds and the last weekend in Feb as the deadline, and if someone else wanted to take me up on that bet they could fill the other side of the bet, put up the H$ needed, and then at the end point of the wager it would cash out in the designated ratios/amounts/whatever to each person.
Maybe this has already been suggested at some point, maybe not. I think it'd be pretty fun.