On a USX (Air Wisconsin) CR2 last winter. Pushed back and then we were smacked with an ATC ground stop from our destination. Captain came on the PA with an estimated wheels up time and went on to say "since were going to be here for 45 minutes or so, why don't you go ahead and pull those Kindles and iPads back out and keep yourselves occupied. Ill give you a heads up when they need to be stowed again for takeoff".