Free Android Phone app: https://play.google.com/store/apps/details?id=com.socrative.teacher
Free iPad app: https://itunes.apple.com/us/app/teacher-clicker-socrative/id477620120?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/teacher-clicker-socrative/id477620120?mt=8&uo=4&at=10l6SU
Website: http://www.socrative.com/
Edmodo app: http://www.edmodo.com/publisher/socrative
Google Chrome app: https://chrome.google.com/webstore/detail/socrative-teacher/ofajgnplnindhnhnconjocimijjifaln?hl=en
Website: http://www.wordle.net/