Huntathon - Browse and submit Product Hunt Global Hackathon projects
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Confs.tech - Open source list of tech conferences: JS / Ruby / Data etc.
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Ha.ckathon - Find the right Hackathons for you!
pretix - pretix helps you to sell tickets for your event in an easy way. It supports multi-lingual events and provides a wide range of features