Phraffle.com - instant raffles using phones as raffle tickets
Suggested Instructions for Audience Giveaways Have everyone stand up. Tell audience to remain standing only while their phone number matches the pattern. Click/Tap the last digit to make it stop spinning. 90% of the audience should now be seated. Click/Tap the next digit and see if anyone is left standing. If not, re-spin it and try again. Last person standing wins. With an audience of 100 people, it typically works between 2 to 4 clicks.
Blog post describing app -- http://gregsramblings.com/2012/05/13/an-interesting-way-to-handle-event-giveaways-phraffle-com/ Blog post describing app cache usage and offline use -- (comingsoon)