The sides of tenements and lofts along Houston St. in downtown NYC are perfect for hanging building-size ads. Not only is the street one of only a few major crosstown traffic arteries, but it cuts through the city's hippest shopping and entertainment districts. Location in part explains this gargantuan sexed-up ad screen for designer and fashion brand Calvin Klein. A sexy couple are virtually dry-humping each other while another shirtless young man sits nearby. (What could is he thinking?) The product might be jeans or cologne or whatever, but this ad is like a giant well-photographed teaser for group sex.