RIM has been showing off some of the elements of Cascades on stage as the UI building blocks of PlayBook and BlackBerry 10 Apps. They call it out of the box elegance. They even flashed back to the homescreen a few times which is built on tiles when you switch between apps with a slick shrinking and growing animation. This is the same animation RIM showed when you peek from one app to the other. It also shows pulling left to see what is going on in terms of notifications.
And the homescreen: