Tynker - Game Worlds for Kids to Learn Programming
ProppyJS - Functional props composition for UI components (React & Vue)
CodeCombat - Learn programming with a multiplayer live coding strategy game.
Appbase.io - Search stack for building modern apps
StackHive - Design, develop or publish websites right from your browser
Deja vu - A mind-blowing interactive piece to promote an album. Wow.