Even if your session is on a serious subject you could well benefit from injecting an element of fun by peppering quiz questions and spot-prizes throughout. If you divide the group into teams you can have them work together and bring in an element of team bonding as you go.
OMBEA can display Participant and Team Leaderboards throughout your presentation so that you can keep people up to speed with their progress.
For more instructions on different competion features within OMBEA Response take a look at our article on Competition Settings.
For inspiration on quiz questions, the following resources may help:
Depending on your location, Google has a nifty trick up its sleeve to help with ice-breaker questions. Just search in Google for ‘Interesting Facts’ and the first result should be a random fact that you can use for inspiration.