If you haven't read Lulu and the Brontosaurus by Judith Viorst go get it now. I checked it out from the library after reading a slew of positive reviews back in December. I thought it would be a good one to read to my girls on the two hour drive to their grandparents for the holidays. It was. They loved it. As soon as we finished they wanted me to read it again. I was unwilling to do so immediately but did promise to read it on the drive home.
My students loved it just as much as my daughters. One favorite part was Lulu's song she sings as she heads off looking for a brontosaurus for a pet. They would be singing it at all times during the day without even realizing. It's quite catchy. In fact, if you are against having it as an earworm I suggest you don't watch the video of the class singing it. (This video was taken so long ago two of those little darlings have moved away.)