Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Ubuntu - Ubuntu is a Debian Linux-based open source operating system for desktop computers.
Event Hunt - Startups and Tech Events Curated By Locals
Debian - Debian is a free distribution of the GNU/Linux operating system.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Fedora - Fedora creates an innovative, free, and open source platform for hardware, clouds, and containers that enables software developers and community members to build tailored solutions for their users.