SignUpGenius - SignUpGenius is a tool for scheduling events, sending out invitations, and managing your respondents all in one place.

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

SignUpster - Signupster is the all-in-one platform that simplifies your sign-up process. From event registrations to membership sign-ups, Signupster offers powerful tools to streamline and manage your sign-ups efficiently.

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

Facebook Local - Discover places to go and events happening near you

Bigtent - BigTent is a web-based organization and communication portal for groups.