There is no single organisation that is responsible for arranging all the events across the world. In fact, a lot of long running clubs began as an idea between a small group of friends that snowballed.
Most organisers work their butts off to run events for the fun of it rather than profit but there are some that work full time to provide high quality LARP too. When deciding on which events to attend, the organiser’s previous events and reputation go along way toward figuring out if it will provide the aspects you are looking for (e.g. customer service, lots of combat or high level of plot detail etc).
You can see some examples of event organisers on our Organiser List.
