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.