Those are some good ones. I fly a bunch for work and have actually heard a few of those or something similar. Southwest is usually the most fun, but recently United has come up with a little humor in their pre-flight video and even the attendants (who all have 40+ years union seniority on the international flights, so usually aren't in a good mood) even crack a smile.
Southwest actually used a couple of these on a flight to Las Vegas. I remember the one about picking your favorite kid. When we landed they had one last funny "Southwest would like to welcome you to the city of Lost Wages."