The Sneetches (pdf), by Dr. Seuss, tells of a group of yellow bird-like creatures called the Sneetches, some of whom have a green star on their bellies. At the beginning of the story, Sneetches with stars discriminate against and shun those without stars.
An entrepreneur named Sylvester McMonkey McBean (calling himself the Fix-It-Up Chappie) appears and offers the Sneetches without stars the chance to get them with his Star-On machine, for three dollars. The treatment is instantly popular, but this upsets the original star-bellied Sneetches, as they are in danger of losing their special status. McBean then tells them about his Star-Off machine, costing ten dollars, and the Sneetches who originally had stars happily pay the money to have them removed in order to remain special. However, McBean does not share the prejudices of the Sneetches and allows the recently starred Sneetches through this machine as well. Ultimately this escalates, with the Sneetches running from one machine to the next…
With his usual flair for rhymes and colorful animations, Dr. Suess shows that when externals are stripped away, we are all basically the same. A great book to teach kids not to discriminate, and to treat everyone with respect.