<I>Knock, knock. <P>Who's there? <P>Lettuce! <P>Lettuce who? <P>Lettuce in, it's cold out here! <P></i><P>From the first knock-knock joke to the last, <b><I>Lettuce In!</i></b> provides the perfect introduction for young joke tellers. With whimsical animal characters and easy-to-follow jokes, this book also features a flap on every spread. The flaps reveal the surprise punch-line to each hilarious knock-knock joke!