What did the mayonnaise say to the refrigerator? Shut the door, I'm dressing. OK, so it's not Noel Coward (or even Neil Simon), but TV fave Rosie O'Donnell has shown a real fondness for this cut-to-the-chase brand of children's humor. When the new media darling asked on her show for samples of similar jokes, she was inundated. Fast forward to April 10, and the publication of Kids Are Punny: Jokes Sent by Kids to the Rosie O'Donnell Show. Already in its third printing, the Warner hardcover has an impressive 386,000 copies in print. It's getting virtually daily exposure, of course, with Rosie touting the book to her mammoth audience (her show premiered last June to the highest debut ratings of any talk show this decade). Additional publicity -- as if any was needed -- has included magazine coverage in People, Time for Kids, Family Circle and Sesame Street Parenting, plus a feature last month on Entertainment Tonight. O'Donnell has announced that all proceeds from the book will be donated to the For All Kids Foundation, an organization devoted to children's charities.