Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Schedule Share - Create and share read-only calendars
emble - Plan better events with your friends
Planmesh - The easiest way to plan with friends
Gong - Gong uses AI to analyze spoken conversations from audio sources and web conferencing platforms such as Cisco WebEx, GoTo Meeting and Zoom.
Calendarscope - Make your calendar fun!