Is this aimed for FP beginners who already know something like Java? I think the thing to do here would be to come up with some tasks that are genuinely tedious to write in a Java-esque (or Pascal-like) language, and then present how FP solutions are simpler.

  I'm of the opinion that FP succeeds not just because of the tenants of FP, but because most of the languages are terse and have code that is "pretty". Showing some quick things involving quick manipulation of tuples (basically a bunch of list processing) could show that things don't have to be complicated with a bunch of anonymous classes.

  Anyways, I think the essential thing is to present a problem that they, as programmers, have already experienced. The big one being "well these two functions are almost the same but the inner-part of the function has different logic" (basically, looking at things like map). Open up the world of possibilities. It's not things that are only possible in Haskell/Scheme (after all, all of these languages are turing complete so..), but they're so much easier to write in these languages.