One game to rule them all
1983 Atari 2600 game, by Activision (programmed by Mark Lesser).
The Lord of the Rings (also titled as Lord of the Rings: Journey to Rivendell, the promotional material says one title, while the box says the other), is one of the rarest Atari 2600 games known. In an odd twist of fate, there is only one copy of the game about the one ring.
This game was featured in Activision's 1983 catalog. But the video game industry had hit hard times, so Activision never bothered to actually get the game produced (despite the fact that it was a finished product). They even lied about the game in some sort of odd effort to cover their tracks (people inquiring about the game would be told it was currently sold out, by 1984 the story changed to "That title has been discontinued"). A few boxes of the game were made for display purposes at trade shows, but the cartridges themselves were never actually made (a few uncased copies were the only ones ever produced).
This game was long thought to simply not exist, until a sealed display box for it turned up on Ebay in Fall 2001. By December 2001, one of the editors of Atariage.com had managed to procure a copy of the actual game (still the only copy known to exist). The game has been dumped, and will work with most newer Atari 2600 emulators (older emulators have problems, because the game is 8K in size, far larger than most 2600 titles).
The game itself is a highly detailed (well highly detailed with bad graphics), adventure game. It is a little confusing without any sort of instructions available.
Here is the official description from the 1983 Activision catalog.
"The Lord of the Rings, Journey to Rivendell is a new adventure game based on the fantasy novels by J.R.R. Tolkien. Relive the adventures of Frodo as he travels from his home in the shire to Rivendell. You'll face constant choices as you journey through Middle Earth, trying to avoid the Black Riders. Use the unique map to pinpoint your location as you move through more than 2000 exciting screens. 1 player."