Reverse Dictionary - Describe a concept and get back a list of words
Outgrow - Enabling marketers boost conversion with interactive, beautiful & viral quizzes/calculators.
Writefull Thesaurus - A Google Docs add-on that uses AI to give you synonyms
Quizzes for Pages - Quizzes for Pages is an application to create and share quizzes on your Facebook Page.
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.
Poll Everywhere - Audience response system that uses mobile phones, twitter, and the web. Responses are displayed in real-time on gorgeous charts in PowerPoint, Keynote, or web browser.