One of my favorite examples of sarcastic back announcing, heard on a classic rock station years ago:
DJ 1: ...Going back to 1931 there with Cream and "White Room." Can't you just hear the flappers in the background?
DJ 2: Yes, I was doing the Charleston.
It was refreshing to hear a morning team have fun with the back announcing, instead of just tossing off a generic slogan such as, "More classic rock every hour."