It's Room One from the Junie B. Jones books! The boys have been fans of Junie B. since Kindergarten. Sure, she overuses the words smelly, stupid and dumb but she's really a funny character. Especially when she's brought to life in theater. We loved watching Jingle Bells, Batman Smells back in December.
In the first Junie B. book she gets locked in the kindergarten building after school. I can remember reading this book one night to Thomas when he was in kindergarten and as I was turning off the light he said, "Mommy, I wish I could be locked in the kindergarten building with Mrs. D." (Mrs. D was one of the very young and pretty kindergarten teachers at his school.) Cute! Of course, nowadays Thomas doesn't think it's cute at all--especially writing about it my blog--more like stupid and dumb but in the words of Junie B: a journal is where you write your life.