Who's there? Santa... elbow. Santa elbow who? Santa elbow... face. HA HA HA HA HA
This is what happens, over and over, when your 4-year-old discovers knock-knock jokes. I'm not sure at what age they actually start to understand them but right now, they are the most hilarious thing in the world and 20 minutes of non-stop, similarly point-missing jokes is apparently a great way to pass the time. Funnily enough, he first one was "Justin", I was expecting "Justin Time" but no, it was "Justin... emm, emm... Leg. HA HA HA HA HA" and it went downhill from there.