The human mind is incredible. It solves problems with ease that will elude machines even for the next decades. This book explores what happens when humans and machines work together to solve problems machines cannot yet solve alone. It explains how machines and computers can work together and how humans can have fun helping to face some of the most challenging problems of artificial intelligence. In this book, you will find designs for games that are entertaining and yet able to collect data to train machines for complex tasks such as natural language processing or image understanding. You will also find concepts and solutions for some of the various challenges of these games.