There's a minor bug in the tournament list. Currently there's an open tourn (Epimetheus Grouped Random) which advertises open to new entrants on the tourn list page.
HOWEVER, if you view the tournament as a non-paying member it says Sorry, you must be a member to sign up).
If, perhaps, you were thus enticed to join the site and try to sign up, it says (in the view page) Sorry, tournament is fully subscribed. Going back to the list it still reports it's open to new entrants.
Perhaps that first text link could be updated to either read open to new entrants or ournament fully subscribed....