Near the end of Return of the King, where we see Frodo writing in the book Bilbo started, during the voice over, what is the last line he writes in the book before closing it?
The book is ‘The Hobbit, or There and back again’.
I don’t know of anything in the Tolkien books which describes this incident, so I assume that Peter Jackson added it for atmosphere.
When the extended DVD version of the Return of the King comes out, there may well be something in Jackson’s commentary that describes this further.
and I know Frodo is writing The Lord of the Rings. But I don’t think the last line of Tolkien’s book is the last line we see Frodo writing in the movie. And the last part of the voiceover is this:
“How do you pick up the threads of an old life? How do you go on, when in your heart you begin to understand there is no going back. There are some things that time can not mend. Some hurts that go too deep…that have taken hold. Do you ever really heal?”
But that seems like such a pessimistic last line for Frodo to be writing. I guess I’m just assuming it’s something a little more uplifting, or at least something with a little more closure.
The textual history of the Red Book of Westmarch (the manuscript shown being written in) is detailed in the Prologue to The Fellowship of the Ring, in a section called “Note on the Shire Records.” In this note Tolkien assumes the role of a scholarly textual editor who has collated old manuscripts and traced the process of how the text was created and then hand copied, and he follows the fate of the various copies, implying that he has somehow gotten a look at one of the manuscript copies and translated it into English, then published it under the titles The Hobbit and The Lord of the Rings. He recounts the authorship of the various parts of the Red Book (for example, Herblore of the Shire and Old Words and Names in the Shire by Meriadoc).
Tolkien tells us about the Red Book
do I need to get ahold of that book to find what I’m looking for?
The big red book doesn’t exist.
I don’t know what the last line ever written in it was because it doesn’t exist and you can’t read it.
Bilbo told Gandalf in Fellowship of the Ring that the book would end with “And he lived happily ever after, to the end of his days.” I expect Frodo followed this intention.
Frodo left the Red Book to Sam Gamgee, telling him “the last pages are for you.” Tolkien does not reveal what Sam wrote. I imagine it would be an account of the final leave-taking from the Grey Havens, and perhaps a little about what came of Merry, Pippin, and Sam.
Since Tolkien’s conceit is that he’s retelling what he found in the Red Book of Westmarch, what you speculate is precisely what Sam wrote, with the famous last words, “Well, I’m back!” 
“…and it was still warm.”
I think it says, “Soylent Green is people!”
Either or that or “Lord of the Rings II, Coming to theatres – Summer 2007!”
Off to Cafe Society.
DrMatrix - GQ Moderator
I think we need more info from the OP:
Is this a “what happened in the book” question, or is it a “I couldn’t read the line Frodo wrote” movie question?
101 Different Ways to Prepare Taters by Samwise Gamgee
If you mean the page he’s writing that’s seen on the screen just before Sam comes in. I’ve tried to read it several times in the theatre and off the DVD; as far as I can make it out, it has to do with Sam getting up nerve to ask “the fair Rose for her hand” (or something along those lines) and there’s a mention of Elanor, but Frodo’s hand is in the way and blocks part of the sentence.
“Disclaimer: The above is a work of fiction. Any resemblance to actual persons, events, or places is purely coincidental.”
Books? They made the movies into books?
I’m fairly sure that whatever Frodo (or Sam) wrote, it wasn’t that! 
An update now that I can look at the DVD: With some pausing, zooming, and squinting, it looks like the last thing Frodo writes in his book (partially obscured by his hand) is, “It was the best thing he ever did.” – presumably in reference to Sam’s marrying Rosie.
Someone with a bigger TV screen or better resolution (and more obsessiveness about this kind of thing) could probably give you the text of the whole last paragraph.
How about
“Old hobbits die hard. The end.”