ronaldmaustin's post about banned items on eBay is a great place to start thinking about what else could be sold there.
I'm surprised someone hasn't yet offered a service to buy people's numbers for PowerBall or other state lottery.
e.g.
http://www.powerball.comI don't play personally, but would be thrilled to see Bitcoin help clear the line in front of me at the convenience store.
Unfortunately, possession is 9/10ths of the law. It would work for all the losers, but if you ever won the big won, good luck getting the ticket receipt from the true purchaser. Even with a pre-signed contract, he would probably fight it, he will have (currently: $40 Million ) to hire Lawyers, you will have a claim and maybe a lawyer.
What surprises me is why PowerBall themselves don't sell through the Net. Just tie the C/C Hash info to the Receipt/email to prove ownership. Only those with the right C/C can claim. And their be no doubt who bought the ticket. Even if fraudsters used a stolen C/C, I bet the true owner would say: Thanks for stealing my C/C and buying Lotto tickets.