Open Prediction Markets

I just realized there are now a few of these, so I wanted to create a list:

• Bookmaker which has releases for 6.x and 5.x, but no commits in the last year.
• Betting which has a 6.x release, and the last commit was 5 weeks ago, but there is an issue in the queue that says it doesn't work.
• Prediction Market no releases and no open bugs, active 28 weeks ago.