Upcoming.org - A simple way to share and discover interesting events
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
TEEM — Meet offline - People & Activities Nearby
Mobilizon - A free and federated tool to get our events off Facebook
Togetheo - Meet people nearby, who share your interests 🌍
DownToMeet - DownToMeet is a platform to organize, find, and attend group events.