Dawn and the Big Sleepover

A bunch of kids at Stoneybrook Elementary have pen pals at a school in New Mexico. The Baby-sitters love hearing the letters that Charlotte, Becca, and the Pike children get from their new friends.
Then the bad news reaches Stoneybrook: their pen pals' school has been destroyed by a fire. Dawn is so upset that she organizes a fund-raiser for them. And as a reward to all the kids who help out, she is going to throw a gigantic sleepover!
A hundred kids, thirty pizzas--will Dawn survive her biggest baby-sitting job ever?