Ranker - Ranker goes far beyond Top 10 lists with deep rankings about everything, voted on by everyone.
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.
Rewala - Decision-making application
TierMaker - Create a tier list for anything
IQ Polls - IQ Polls is an interactive polling tool for real time audience engagement in conferences.
Clever - syncing between education applications for K-12 schools