Everybody loves something free but it's even better when you WIN something for free. This is the simple principle behind contests; it taps into our competitive spirit and is a good motivator for action.
To be effective a contest has to have a great prize and the process of entry has to be simple. It should also be compelling enough to share with others. You might be thinking that contests are hokey; I'm here to argue otherwise. For most my career...
I used to play the silver ball. From Soho down to Brighton I must have played them all. Well, actually I've only played pinball a handful of times but this post gave me a chance to riff lyrics from The Who, so I couldn't resist being dramatic. I do love a pinball machine, however. They're tactile and responsive; You feel part of the machine. The ball is unpredictable but if you hit the right places it increases momentum and triggers additional events, more balls, and more feedback....