Simply Piano - Fast and fun way to learn piano

Reverse Dictionary - Describe a concept and get back a list of words

Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.

Silicon Valley Dictionary - Urban dictionary meets Silicon Valley

Yousician - Learn to play music at home, at your own pace

Dictionary Anywhere - Dictionary Anywhere is an open-source and easy-to-use browser extension for Mozilla Firefox and Google Chrome that allows you to check definitions easily while browsing the web.