Posting a joke and using a joke before a live audience is quite different. Making it sounds real before the punch line enhances the punch line.
Here is one that I used twice recently that went over well.
Snice there’s so many new people here since the last time I was here I feel a need to reidentify myself. My real name is Richard, but I go by Dick. In the first grade there were five Richard’s, so we all got nick names. Our sweet first grade teacher said this is the beginning of your formal education. From here you will go on to high school and maybe college. You can be anything you want in life, but it starts here. Study hard and follow your dream. Is there anybody here this morning that has a dream. I do, I do. Yes Dick. I am going to join the Navy and become a pilot and make enough money to start a company to build jets and train pilots. Then when I have lots of money, I am going to build a new house on top of the highest hill for my wife. She will have lots of rooms, servants, and a new car every birthday. That’s quite a goal Dick and its possible if you work hard, but probable not realistic. Is there anybody in class that has a realistic goal. Me, me. Yes Jane. I am going to be Dick’s wife.