Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
DragonBox Numbers - Teach kids about numbers with an easy and fun game
Zorbi - Spaced-Repetition Flashcards - Other tools are built by boomers, Zorbi is built by students.
Wikids - An encyclopedia that talks to your kids
SmartCards+ - Spaced Repetition Software for iOS. Modern, powerful and easy to use.
Four Seconds - A timer and a simple rule: stop it at exactly four seconds.