This incredibly-comprehensive, perhaps exhaustive, campaign for "The Dark Knight" won the Cyber Grand Prix in the "viral" category at the Cannes ad competition last week, but over and above (perhaps that should be "beneath and permeating") the campaign was the ongoing use of Surprise as a driving force.
Phones in cakes, hidden bags in bowling alley lockers; tactics like "Time Bombing" and "Looking in the Rear-View Mirror" outlined in the Pow! book were put to good use...much to the delight of not just everyone at Surprise Central, but obviously to hundreds of thousands around the globe.
Little things mean a lot in Surprise marketing, but see what happens at the other extreme when you decide to throw a lot of money, time and brilliant people at it: