Foundler - Online hackathon weekends. Attend every other week.

Akinator - Akinator is an entertainment app that acts like a digital genie that can read your mind. The game will ask you a few questions about the character you have chosen, and it will attempt to guess the character from your provided answers.

HackHub - Host tech events and hackathons with ease 👨‍💻🛠

Trivia Crack - Produced by Etermax, Trivia Crack lets players answer trivia questions and compete against other people on mobile devices.

Confs.tech - Open source list of tech conferences: JS / Ruby / Data etc.

A Google a Day - Online trivia game where you use Google's search to answer questions as fast as you can.