Have they read “Bored of the Rings?” http://en.wikipedia.org/wiki/Bored_of_the_Rings
I think my 16-year-old has. It’s on a shelf at the top of a closet, with other books we either don’t want them to read, or don’t want them to destroy (like the complete set of Horatio Hornblower novels).
I’m currently reading Tolkien to “teh byos,” who are 11, 9, 7, and 4. Sometimes the teenage girls (13 and 15) show up, too, if they’re not being allowed on the computer at the time. I tell them that every page has at least one word they might find on the SAT.
BOTR ... The adventures of Dildo Bugger. If one is a fan of the LOTR but retains a sense of humor the first couple chapters will leave you doubled over laughing. After that it gets sort of old.