An advertising company came up with this ingenious interactive billboard for a cafe in São Paulo, Brazil.

This is pretty clever. Everyone knows yawns are contagious, but until now, nobody had harnessed that power to sell coffee. The clever folks at Lew'Lara/TBWA, a Brazilian ad agency, have changed all that.

This high-tech, ingenious billboard they placed in the São Paulo subway senses when people walk by it. Then it displays a video of someone yawning, and points out that they should be drinking coffee – coffee from the advertiser, Café Pélé. It's kind of manipulative, sure. But very neat.

My biggest question is: why does a place called Café Pélé have to advertise in Brazil? Isn't it the law that you have to buy everything that says Pélé on it there? I'm just assuming.

Sources: Lew'Lara/TBWA