The Henry Ford Invention Convention Worldwide

SAE A World In Motion (K–12 engineering education program)

International Bridge Building Contest

FIRST Robotics Competition (FRC, FTC, FLL)

VEX Robotics Competitions

MITES (MIT Introduction to Engineering & Science)

EngineerGirl Writing & Design Contests (for girls)

Instructables (upload your own inventions/projects)

Hackaday.io Projects (advanced makers & engineering)