He told the one about the psak not to smoke which in the American version goes
After it was decided it that smoking was against Halacha (which it of course is [even if you are addicted]) the Orthodox, Conservative and Reform Rabbis get together to decide what to do.
The Reform Rabbis simply decide that since this is a Halachik ruling they can ignore it.
The Conservative Rabbis decide that from now on Conservative Rabbis will no longer smoke.
The Orthodox Rabbis decide that before a Jew may smoke he must sell his lungs to a Non-Jew.
The Israeli version which doesn't play on movements that don't exist in Israel, simply has a guy taking a neder (oath) not to smoke. Making the same point about the legal fiction of Matana Al Minat L'Hachzir (A gift on the condition of return) and the general idea of selling Hametz on Pesach.
This of course relevant to Heter Mechira. Some Talmidim were complaining about it, so he said everyone sells hametz on pesach, and eats hametz that was sold by big companies over pesach.
Then the other really good joke which has a good moral that he told goes as follows:
A rav of a town was very respected and served his congergation day and night. After many years this exuasted him so he decided to go on a short vacation. The community was petrefied, what would they do without the Rav. As the Rav leaves he gives intsturctions as to how to check if meat is kosher. He tells them to throw any questionable meat to his dog. My dog is smart he says, he knows you are supposed to throw treif meat to the dogs, so if he knows its treif he will eat it. If he doesn't' eat it, then its kosher. After a few weeks teh Rav comes back and everyone is so happy to see him. The first thing they say to the Rav on his return is: "We are so glad to have you back, your dog is so machmir!(gives strict rulings)"... Which goes to teach any old dog can be machmir, but it takes a real Rav to be meikil.
And just to add in a joke which reminded me that I wanted to post this, from MomInIsrael
A girl comes to her father and announces her marriage plans. When the father asks the boy's occupation, the girl tells him that he is a chazan (cantor). The father says, "No daughter of mine will marry a chazan!" The girl and her mother cry and beg, but the father is adamant. He won't consider a chazan for his daughter. Finally, they convince him to go to shul to hear the potential chassan (groom) in action. After the davening the father comes to his daughter and wishes her mazel tov. The daughter, delirious with joy, asks her father what changed his mind about her intended. He replied, "I heard him, and he's no chazan!"
(Unfortunately, the bar mitzvah speaker who originally told this joke concluded by saying that the bar mitzvah boy was also no chazan, but had other wonderful qualities!)