Ludus - Limitless creativity for your slides.
Kahoot! - Kahoot! makes it easy to create, play and share fun learning games in minutes—for any subject, in any language, on any device.
SlideLizard - Powerpoint plug-in for live audience interaction
Sli.do - Slido is the ultimate Q&A and polling platform for live and virtual meetings and events. It offers interactive Q&A, live polls and insights about your audience.
Zeetings - Turn your presentations into interactive conversations
Mentimeter - a web-based polling tool for workshops, conferences & events