I had the most amazingly, wonderful opportunity to work with Donna Glynn of Kinderglynn on a unit based on Eric Carle's book House for Hermit Crab. She was absolutely fabulous to work with and such a blast! I'm sure you all already know her but if not you have to go check out all of her fabulousness.
I love using books to develop themes around and House for Hermit Crab is a great children's book for the end of the year and even the beginning of the year. It's about a little hermit crab who finds a shell (his new home) and makes friends each month throughout the book. At the end he gets too big for his shell and has to find a new one and leave his old shell and friends behind -- just like our little students grow throughout the school year and have to move on to new class with new friends.