How does a person remember ads? BMW will tell you. BMW flashed an audience with a blinding light that included a cutout of their logo. When the audience was told to close their eyes, they still saw the letters: BMW.
The video explains that the effect it's akin to staring at the sun for too long, when you close your eyes, you can still sorta see a spot there (or go blind). BMW used that to their advantage, flashing a bright screen during their commercial that included a cutout of the letters BMW, so when the audience was instructed to close their eyes, they saw BMW projected against their eyelids.
It's creative advertising (and they say it was harmless) and the focus group seemed mightily impressed with the effect. It tied into the commercial quite nicely too, check out how it was done in the video above (though the flash effect doesn't work over YouTube). [Wired]