Guestboard - Lead powerfully-organized group events with Guestboard – a modular event platform that gives groups of 10-1000+ people a central space to coordinate, build excitement, and save money. No more crazy email threads. No more massive group texts.
RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.
Mobilizon - A free and federated tool to get our events off Facebook
Evite - Send online invitations for all occasions by email or text message. Create invites for birthdays, baby showers, save the dates, or customize your own design.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
JustRSVP.me - Online Invitations and response tracking for weddings, baby showers, birthdays, parties, and other...