It's open Saturday, but the X-ball field is a private field. So in order to play on it, your team has to schedule matches through Byf8th or Ghetto Smurfs. They own the bunkers. You can contact them through: www.pbaz.com
That's the Arizona Paintball forum
As for Sunday, I don't know if 23 will be open or not. There is a rumor that Dynasty & Russian Legion will be scriming on the X-ball field, so it may be closed for the public.