Here is a neat look at a recent cinema advertising campaign undertaken by BMW which utilizes a phenomenon called the After-Image Effect. The After-Image Effect is the visual effect one experiences when looking at a bright light source (such as the sun or camera flash) and the spots one sees when closing the eyes immediately afterwards.
In this ad, the BMW letters flashes momentarily towards the end of the ad and the viewers were asked to close their eyes immediately after conclusion of the ad spot. What they saw was a lingering BMW sign. Viola, the first advertising commercial that doesn't use a directly visible logo! Oh, and the ad isn't too shabby either - featuring sportbike champ Ruben Xaus.
* Note: this does NOT work by watching the video, only for those who see the ad in person