Slope Game 3D's answer
Fun and unique gameplay
Agar.io - The smash hit game! Control your cell and eat other players to grow larger! Play with millions of players around the world and try to become the biggest cell of all!
Clever - syncing between education applications for K-12 schools
Chess.com - Play chess on Chess.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Terraria - Dig, Fight, Build! The very world is at your fingertips as you fight for survival, fortune, and glory.
Claroline - Claroline is a collaborative eLearning and eWorking platform.