Apple approached Christian Marclay to use his video Telephones for an iphone ad. He refused so they decided to rip-off his idea. Marclay's video used short clips featuring phone calls from classic Hollywood films. He decided it was unwise to sue Apple in part because he has used his clips without permission. But the obvious difference between the 2 cases of copyright infringement is that Marclay montaged the existing material together to create something new whereas Apple have just copied Marclay's idea. Here are two youtube videos the first showing a clip from Marclay's film from a documentary about his work and the other showing the rip-off ad.
This story comes from the ny times