Eats, Shoots and Leaves
This is a really nifty little picture book that illustrates the importance of commas through the use of simple sentences with humorous illustrations contrasted with the same sentence (on the opposite side of the page) differently punctuated. The results are entertaining and quite educational.
Here is one example:
On the left-hand page is the sentence: "Slow, children crossing." The cartoon-like picture shows a crossing guard signalling for cars to stop while some school children cross the road.