Gabrielle is currently doing a survey of LOTR cast members' past and future lives. Not in a reincarnation-wheel-of-life way, but just poosting on movies, before and after, that some of the cast have made. If you're looking for some good "sorta lotra" stuff to watch then you can go read the results of her research.
Here is my own little variation of the game, which is "What actors have acted with two or more LOTR actors in different movies?" Sort of a six degrees of seperation thing.
So far the list is a short one, and not necessarily exhaustive since I am going off the top of my head:
Johnny Depp: With Orlando Bloom in Pirates of the Caribbean, and Cate Blanchett in The Man Who Cried.
Ewan McGregor: With Christopher Lee in Attack of the Clones, and Orlando Bloom in Blackhawk Down.
Famke Janssen: With Elijah Wood in The Faculty, and Ian McKellen in X-Men and X2.
Josh Hartnett: With Elijah Wood in The Faculty, and Orlando Bloom in Blackhawk Down.
Harrison Ford: With Viggo Mortenson in The Witness, and John Rhys-Davies in Raiders of the Lost Ark/ Last Crusade.