Kahoot! - Kahoot! makes it easy to create, play and share fun learning games in minutes—for any subject, in any language, on any device.
ViralSweep - Grow your fans and increase sales with sweepstakes and giveaways.
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.
Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.
Mentimeter - a web-based polling tool for workshops, conferences & events
KingSumo - Grow your audience with viral giveaways that cut marketing costs