I would like to know how to set up Admob Interstitial ads when I present my GameOverScene. What should I do to show the ads only sometimes when the game gets over? And how d
why dont you use NSNotificationCenter or delegates to call showInterstitial().
For example
In gameViewController add this in viewDidLoad
NSNotificationCenter.defaultCenter().addObserver(self, selector: "showInterstitial"), name:"showInterAdKey", object: nil);
and when you want to show the ad from your scenes you use
NSNotificationCenter.defaultCenter().postNotificationName("showInterAdKey", object: nil)
You could also use something like the helper I posted on github which makes this even easier and your ViewController stays clean https://github.com/crashoverride777/Swift-2-iAds-and-AdMob-Helper