Cat in the Hat with Thing 1 and Thing 2?! I think the girls and I might need to be this for next year!
Chicka-Chicka Boom Boom Costume Pattern and Instructions from About.com
(This is just adorable, I think!)
Any of a number of literary owls such as Sam: DIY owl costume instructions
Our Put Me in the Zoo costume!
And we can't forget Madeline...
What about you? Do you have any fun book-inspired costume ideas to share?