Check out this product page from Dutch department store HEMA. I have never seen anything like it (wait for a few seconds for the fun to begin, and turn the sound up if it won't give away the fact that you're goofing off to your boss).
Lessons for meeting planners? None that I can think of, other than if you make your registration page fun in some way, people might pass it along to others the way someone (thanks!) passed this product page link along to me.