Today is Polar Express day at Caleb's Creek Elementary, which means in addition to wearing pajamas and consuming loads of hot chocolate, there are lots of lessons integrating the book The Polar Express by Chris Van Allsburg. If you are looking for ideas, there are tons of sites with compilations of links to lessons such as Education World, Busy Teacher's Cafe, and Houghton Mifflin, among others.
Some of the best ideas I saw involve elements of the book like using it to study the use of metaphors and similes, point of view, and writing your own version, but could also be a great way to do a lesson on adjectives to describe what you would see, using your 5 senses, writing or following recipes (what if you had to quadruple a recipe for everyone on the train?), showing just one illustration and have students write using that as a prompt before reading the book, and so many more. What if stories could be great also - what if the train broke down, what if you were chosen, what if you got to spend the night travelling with Santa, what if you were Santa?