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

Briar - Secure messaging, anywhere

Event Hunt - Startups and Tech Events Curated By Locals

Bridgefy - Integrating Bridgefy allows mobile devices to communicate in a secure and efficient way across...

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

The Serval Mesh - It works by using your phone's Wi-Fi to not communicate with other phones on the same network.