I believe most of the sites on the Merge Network have a lot of bounty tournaments. I used to play them all of the time until I cashed out all of my Merge accounts. They even used to have a Bounty Leaderboard, where you would get ranked based upon how many people you knocked out and what their rankings were(supposedly like chess rankings?) and at the end of the month, the top 100 or something people would get a big freeroll, can't remember how much it was, probably like $5000... but those bounty games were fun, you could get 2nd or 3rd place and still make more than 1st if you knocked more people out.