Here’s a cool demonstration of pure engagement. No, it’s not an innovative new media idea or the hottest viral on YouTube. It’s a “How tall are you?” measuring stick. As kids most of us had our growing height pencilled on a door frame somewhere in the house, and as parents, most of us followed the tradition. Watching the kids inch up to their adult height is one of the great pleasures of parenthood – until they creep past you, that is. What’s riveting about this ruler is that it opens up the height competition far beyond your own family and the kids next door. Now you can measure yourself against great icons of today and yesterday. Are you taller than Peter the Great? Not unless you’re playing on a basketball team somewhere. Are you a few centimeters taller than Brad Pitt? Venus Williams is. And what about Danny DeVito compared with Mother Teresa? It’s Danny by a whisker. OK, most of the names are entertainers but there is a peppering of sports stars and royals for spice. What’s engaging about the idea is the density of associations these names have and how cool it is to see unlikely people placed side-by-side. From this experience one thing jumps out: the importance of surprise to engagement. We keep on checking and comparing the names because we like to have our assumptions confirmed (I’m right!) and we also like the spark of a new association (What?) even if it’s about something as quirky as height. On its own, knowing Arnold Schwarzenegger is 187 cm tall doesn’t grab me, but the knowledge that Maria Sharapova is as well …. Queen Elizabeth II and Drew Barrymore. Gwyneth Paltrow and Johnny Depp. Salvador Dali and James Dean. Odd couples all. Where do I stand? I’m not telling, but it’s somewhere between Paris Hilton and Clint Eastwood.