Patricius, over at Singulare Ingenium, has a Christmas Quiz all about J. R. R. Tolkien, and two of his most famous works, The Hobbit and The Lord of the Rings. There are 25 questions, and it's a multiple choice quiz, so you can have a total guess if you're not sure. It's quite a challenge, and there's a prize of a book up for grabs: The Ring of Words: Tolkien and The Oxford English Dictionary.
Go on... you know you want to!