DO MAGNETS!!!!!
Don't do stickers. Is yesterday. Magnets wind up everywhere.
Do a "BIG CONCERT" contest:
Put a unique concert logo/picture on the back of one of thousands o' magnets.
Middle of night, recruit as many interns as possible to plaster them on metal items all over town.
Next morning roll out promotion "Last night while you were sleeping, we..."
This distributes the magnets AND creates viral commotion.
First one to deliver the winning magnet gets the cool prize.
Magnets end up on cars, desks at work, AND refrigerators at home (you know, next to the diary).