I teach spec ed w/ middle school kids and use Dr Seuss all the time!!! Dr Seuss books all have themes that work w/ the older kids - The Lorax works well w/ 8th grade earth science as well as 7th grade Life Science.....The Butter Battle Book works great w/ 9th grade American History as it was written about the cold war era of who was going to drop the nuclear bomb. The Cat in the Hat has a theme of pick your friends carefully, some can lead you astray if you don't pick them right.
Green Eggs and Ham is about not being afraid to try to new things - AND it was written on a dare. The dare was that Dr Seuss could write a book using less than 50 words - I believe it uses 49 words.