These are typically made up of (but not limited to) Teams, Clubs, Leagues, and Associations.  Teams might want to us to communicate their try-outs on a particular date and time.  Clubs might be promoting communication about their awards banquet function.  Leagues use this as a tool to communicate various age based playing opportunities.  Associations might like to communicating their Annual General Meeting event to their members.

Some events are free, some are paid-for, and some are partially sponsored.