I just saw this building on Really Big Things. That cantilever (huge lip on the side) is especially amazing. It's designed as a party deck for weddings and such.
But the engineers were worried that if hundreds of people were dancing to the same beat, then that might make it unstable since every object resonates at a certain frequency. So they had to have an engineer sit down with an iPod and thousands of songs and test them all. Theoretically, there are some songs that the deejays aren't allowed to play.