> Why can’t I work on an existing project?

Man I'd love to join a hackathon where you are encouraged to work on your personal projects, and you get to share it with other attendees, and they get to share theirs with you, and hopefully someone finds your project interesting and then it's not a 1 man project anymore or vice versa.

Most (if not all) hackathons in my country are sponsored by companies to try out their new api's, gather potential hires under one roof, or for investors/business people trying to find developers/co-founders.