Book it is a program
sponsored by Pizza Hut
designed to encourage grade school
children to read
When a child reads a certain number of books (usually set by the school), said child recieves a certificate for one personal pan pizza (the really, really small ones designed for a single person). Should all the children in a homeroom meet their reading goal, the homeroom gets a pizza party.
The program works suprisingly well. I remember looking forward to it eagerly when I was but a brat.