Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

ENDALGO - Team and league management for the social athlete

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

Sports Bridge - Find a sports team for your child

Bylde - Bylde is a SaaS platform you can use to Start, Manage and Grow your groups and communities.

Athlete Builder - Get better at your sport (mostly football right now)