Heroes of Newerth or HoN as it's mostly called is an older MOBA franchise that came before Dota 2. The game is really good and had a lot of similarities to Dota. They really filled the gap for the competitive MoBA player that had grown tired of the first Dota game but still wasn't interested in League of Legends. Unfortunately when Dota 2 launched it lost a lot of its player base.
The game is played five versus five in competitive games and requires the same skillset as the other MoBA-games. There are not a lot of bookmakers that are accepting bets on HoN, but lately, some of the more eSports focused betting sites have begun offering markets for the few events that still run.