A horse walks into a bar and gets terribly drunk the night before an important racing carnival. The next day the horse is judged unfit to race and is executed. The barman is found guilty of serving alcohol to a visibly intox­icated horse, and is executed.

My daughter has discovered ‘knock knock’ jokes.

I forget jokes quickly, even ‘knock knock’ jokes, but some quick thinking on my part recently meant I was able to entertain my daughter with some rapidly transcribed entries into the canon. For example: ‘Ifor. I forgot my keys’ and ‘Fixyour. Fix your doorbell, I’m tired of knocking’.

No, not exactly Oscar Wilde, but enough to start my daughter thinking beyond the format of:

“Knock knock”

“Who’s there?”

“[Name of ordinary household object within direct sight, eg. curtains, Lego, sock]”

“[Ordinary household object] who?”

“[Repeat original response and append the word ‘bum’, before throwing back head and laughing uproariously]”.

In fact, no sooner had I broadened her horizons with a little meta-humour (“Knock knock” “Who’s there?” “Who.” “Who who?” “What what?”) than she was ready to take flight with something a little more sophist­icated of her own.

“Knock knock,” she challenged. Her look said ‘I’m throwing away the rulebook here, and the rulebook is called Caution, and what I’m throwing it into is the effing wind’. But there was something else: uncer­tainty, fear at her own aspir­a­tions, a flicker of hesit­ation in her eyes. Had she gone too far, too soon? Whatever her punchline was going to be, was it too late to figure out a way of adding ‘bum’ to the end of it?

“Who’s there?” I answered, betraying no sign that I had detected any flaw in her mettle.

“Knock,” she declared, surer now of the strength of her material, a smirk playing at the corner of her mouth as she sensed the full magnitude of the psycho­lin­guistic victory she was about to enjoy over me.

“Knock… who?” I quavered, as though suddenly and hideously aware of the scale of my impending defeat.

“Knock… KNOCK!” she answered.

And she threw back her head and laughed, and so did I, because she had turned the joke upon itself, you see, made it infin­itely recursive, twisting it into the form of a pretzel that has been swallowed by a snake that, remaining peckish, then eats its own tail, and nobody had needed to append the word ‘bum’ to anything, and then I immedi­ately dashed to my computer to write down her joke so that I didn’t forget it, which brings us back to my original point about not being able to remember jokes very well; again, somewhat like the pretzel-eating ourou­bouros I mentioned earlier.

And that is how ‘knock knock’ jokes are made, always and forever.

Yesterday I spoke to ABC 666 Canberra about the death of Elisabeth Sladen, who played legendary companion Sarah Jane Smith on Doctor Who. You can hear the interview below. (Note: you may think you hear the presenter calling me ‘Chris Smith’ at the end, but you’d be wrong.)