It would be quite nice to be able to bet on a game of NFL Madden or NBA 2K.
I have something in the works to set something like this up but currently it's on the shelf behind many other projects.
The real problem that I haven't figured out yet is how to get the casual gamer to participate. People who are good and know certain 'spam moves' and glitches will always be down to put out money as it will yield positive results, but how do we reach someone who wants to play for fun with a bit of money or Bitcoin involved without getting his ass handed to him everytime.
I would give it a go.
I would love to bet on Hearthstone by Blizzard. It is a free to play (somewhat) card game that is short, balanced, and fair. I would totally pay 2 percent of my winning to a service that provided the opportunity to do that.