When show-and-tell becomes all about the latest gadgets and newest stuff, Sister and Brother come up with an item for Sister to present that breaks the consumerist mold.It all starts with a cellphone. After that particular day's show-and-tell, all the cubs go home and beg for one of their own. Some parents give in. Some do not. On the next scheduled day, Sister brings in her Bearbie doll, but before it's her turn, a friend presents the new Fit-and-Trim Super-Exercise Bearbie, and suddenly Sister's Bearbie looks plain and boring. On the way home, Brother helps a glum Sister think of a solution, and the two raid the attic; the perfect thing turns out to be old, interactive, but non-electronic: a Twirl-a-Hoop (readers will know it as a hula hoop). It is a huge hit at the next show-and-tell, and not just among the students: Teacher Jane and Principal Honeycomb even take turns. Unfortunately, the tale ends there, and readers will never find out if Sister has changed the show-off nature of her class' show-and-tell presentations. And while Sister and Brother's mission is an admirable one, it's rather unlike children of their ages. The look of Berenstain's illustrations fits seamlessly with earlier series entries by his parents. Although the message that newer is not always better will be welcome with caregivers, it's unlikely this book will change any children's minds about trying to top their classmates' latest and greatest gadgets. (Picture book. 4-8)