Dood : The Puzzle Planet - A strategy puzzle game for the smart ones
Startup Toolkit - Interactive how-to guides to launch your startup
Ecovolife - A cute farming game which you can immerse your life into
Techstars Entrepreneur's Toolkit - Online resource to help you learn about entrepreneurship
63 - 63 is a race against the world.
AwesomeHunt - Community-curated lists of learning resources on any topic.