When I'm doing stuff like AirDisplay mirroring to my TV or even when I hand my iPad over to a friend to show them something I don't necessarily want the banners from my text messages or emails to show up over whatever it is I'm doing around other people. Short of going through and shutting Notification Centre off every time, is there a quick toggle a la SBSettings that will keep the banners/alerts from appearing when I don't want them to?