Create a joke in the style of Don Rickless that is not too insulting, but still is funny.  It should come across as good natured and not mean or rude.  Also, do not make it a direct copy of any known joke.
Sure, here's a joke in the style of Don Rickles:

Hey, have you seen my doctor lately? He told me I needed to stop eating donuts. I said, 'Doc, I can't help it, they're just so darn delicious.' He said, 'Well, how about you just have half a donut?' I said, 'Doc, you must be nuts. Who eats half a donut? That's like trying to stop watching a Seinfeld rerun halfway through.'