QuizUp - QuizUp gives you the opportunity to test your trivia skills against friends and strangers throughout the world.
Workshop - Learn new skills simply by doing them.
A Google a Day - Online trivia game where you use Google's search to answer questions as fast as you can.
Learn Anything - Search Interactive Maps to Learn Anything
Trivia Crack Kingdoms - The amazing quiz game that lets you test your knowledge and challenge your friends to see who is the smartest. Developed by Etermax
Mindspace - Free learning platform with quick and simple crash courses.