I just read an article in the Brittish "Guardian" by Richard Dawkins and Jerry Coyne. They enumerate a great list of scientific controversies that should be taught alongside established theories in science classes (besides the evident "intelligent falling" of course .
Among the items in the list are such gems as teaching alchemy in chemistry class, phlogiston in a physics class or the stork theory in a sex education class. A real good one (especially from a German perspective) is the suggestion to demand equal time for the theory that the Holocaust never happened in a class on 20th-century European history
What else can we come up with?
Another good point the article makes is the falsifiability of evolutionary theory: