Plenty of teams use a picture board to "signal" in their play these days. Fans are fascinated by this (think of the Chip Kelly ESPN commercial as an example).
Recently, a Tulsa TV station decided to go over to Tulsa football to ask about how they use the picture boards.
The video is priceless. Offensive quality control Corey Heinz is on camera and is asked to explain the board. Watch him attempt to do so without revealing what the picture of Erin Andrews represents.
Perhaps a freudian slip when Heinz at the end says, "one of these could be hot..." and then he looks off camera at the other guys in the room who undoubtedly are cracking up off camera.