Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Foundler - Online hackathon weekends. Attend every other week.
Gigwell Productivity Suite - Streamlining bookings between live entertainers & venues
HackHub - Host tech events and hackathons with ease 👨💻🛠
Bar Car - Become the greatest event host ever with this mobile bar
Confs.tech - Open source list of tech conferences: JS / Ruby / Data etc.