Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Jersey Watch - Jersey Watch is sports management software specially designed for the teams and leagues for organizing players, managing payments, and effective communication.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
TeamSnap - Sports Team, Club & League Management Software & Apps
Bigtent - BigTent is a web-based organization and communication portal for groups.
SportNomad - Run new places. Discover yourself & world