Check out the Trello board if you want to contribute.
A huge map where users play around, drive/race/dm/rp/etc Players create events where people join using a menu or get to the event location events happen at the same server and map, but different layer where other players (other events/main world) are not visible or collide and event objects cannot be seen between layers (checkpoints, entities, etc)
Let's take a race event for example
Nick opens an event. John drives to the event location, a popup appears asking if he wants to join the nearby event. John accepts the event. Matt, Nathan and Dimitri do the same. After the required slots are filled (in this case, 5 or whatever the event creator decides) the event starts, users are teleported to the different layer, placed into cars and the event starts (checpoints initiated, timer, finish line, etc)
Players can create their own event and choose which type, how many slots, password-protect the event, and so on. Players which are willing to join an event (if we do the drive to event thing) have a minimap/map with every event listed at which position it is at