Book excerpt: From the Borscht Belt shtick of Rodney Dangerfield to the urbane wit of Jerry Seinfeld, Jewish humor has had an enormous influence on modern comedy. Jokes about doctors, jokes about food, jokes about mothers--101 classics are in this book, along with witty essays and charming cartoons by Joe Kohl. 101 Classic Jewish Jokes is a must for every fan of Jewish humor--and anyone who needs a good laugh.