A hot topic right now is gamification at trade shows. It was inspired by a mobile video game app built by Hanley Wood for their annual conference and talk soon turned to what the key elements are of a successful trade show game actually are.
Whether it was for mobile or in-person events, the consensus seemed to be that every game should start with a clear and well-defined strategy. Coming up with a good game strategy doesn't actually have to be that hard so long as you use the 4 Design Elements of Gamification.