All games will automatically start with the Halloween Gambit striking out of the Four Knights position; 4. Nxe5, where the uninitiated think that white has blundered away a knight.
If you haven't played it, here is one of the places you can find out more about it; www.chess.com/groups/home/red-army and you are welcome to join, or look it up yourself online. Turn up unprepared and you're in for a messy demise.
Prior to getting some experience with this gambit, it is hard to find the better moves early on. Some of the natural moves lead to disaster for black. Equally white needs to keep piling on the pressure to achieve sufficient compensation for the knight. Therefore only the bottom 50% fail to make the cut each round, to give everyone a chance to become familiar with the best lines and create very competitive final rounds.
Good luck and enjoy!