From 2000, teams, mainly, from Finland, Sweden, UK, Scotland, Russia, Holland, Iceland and Scotland, dispute the World Championship (every year). In the last World Cup, almost 30.000 people were around (players, sponser, attendance..etc..)
The surface for the competition, obviously, is mud.
The dimensions of the fields are: 65X30 m2
The match is 20 minutes (2 halfs of 10 minutes). If they need, it will be an extra time of 10 minutes, with a golden goal.
The team is: 1 goalkeeper and 5 players. In mixed teams, there must be at least 2 women in the team.
Finally, there are no offsides during the match.
There are more rules, but I have only explain the most important, to let you know something else about the competition.
I attach some pictures and a video (in finnish) where you can watch some plays.