I've been debating posting about this for a while, and then just decided, what the heck. Every librarian has his or her own unique way of introducing the theme of storytime for the day. My co-worker who left for a different position made this big "Mystery Book" as her prop for introducing the theme, and she had to leave it here when she left. I wanted to share the idea because the children LOVE it, and it creates a bit of suspense and anticipation about the theme.
My co-worker used one of the GIANT boxes of Whitman's Chocolates as the "book," and she covered it with contact paper and lettering cut out on the Ellison machine. If I were going to start from scratch I would design it to be more attractive (in particular, to children), but it serves its purpose and the kids really do love it.
So at the beginning of every storytime, we say this little rhyme:
Reading is great, let's take a look,
(make a book with your hands, then make binoculars with your hands)
what's inside the Mystery Book? (shrug shoulders in question)
Then the theme of the day is revealed with pictures and then storytime begins with great excitement!