Games with a Purpose

"A human-based computation game or game with a purpose (GWAP) is a human-based computation technique in which a computational process performs its function by outsourcing certain steps to humans in an entertaining way." -- Wikipedia

• Duolingo GWAP for getting translations
• Phrase Detectives GWAP for annotating anaphoric links
• Ontogame GWAP for semantic content creation
• Verbosity GWAP for collecting common sense knowledge
• Wordrobe GWAP for annotating homographs, word senses and pronouns

Related

• Mechanical Turk
• Mindpixel
• Open Mind Common Sense