Social media marketing entrepreneur and creative events coordinator. Fancier of international start ups.
Gameify-ing is the way to go and the entertainment industry will love you for it, so that means get ready for copycats. It should be a plug in to whatever site you are finding that your audience is stuck on. For example, many don't want to leave Facebook. Make it an app for that format. Hope this helps.
I would implement a "bring a business associate" promo. This would entice others to bring a friend at no additional cost; essentially 2 for 1.