Entertainment Weekly will contain video-in-print advertising in september. From the BBC:
The slim-line screens - around the size of a mobile phone display - also have rechargeable batteries.The chip technology used to store the video - described as similar to that used in singing greeting cards - is activated when the page is turned. Each chip can hold up to 40 minutes of video.
Update: Cory has more details on this, and they are not pleasant details.