Program aims to keep school jokes from going nasty Anyone who's ever attended elementary school knows that children love to tell jokes. Knock-knock jokes, in particular, are a favorite among the 11-and-under crowd, along with those that make a silly play on words. Q: Why did SpongeBob put a clock on the stove? A: He wanted to see time fry. At a certain age, though, innocent joke-telling has a way of developing into making fun of others. A funny haircut, a few extra pounds on the belly, an unusual accent or unfamiliar religious beliefs -- it's all fodder for the...