If you've ever played Dungeons and Dragons or, for that matter, any other pencil-and-paper role-playing game, then Neverwinter Nights from developer Bioware will definitely pique your interest.  Neverwinter Nights and its plethora of expansion packs is pretty much a literal paper-to-computer translation of the Dungeons and Dragons rule set.  It even bears the label of the well-known Forgotten Realms franchise.

Neverwinter Nights starts off small but quickly plunges you into the world of Forgotten Realms.  The story in the main game is long and engrossing; once you complete it, however, there are an additional two complete expansion packs and a third expansion pack stuffed with extras and Dungeon Master development tools.  Yes, you can be the Dungeon Master yourself.  You can even take your own game online to play with your friends.

Stories 7/10

It seems like Bioware put more into the actual game engine than the stories themselves.  The main quest in the core game starts off by pitting your character against a horrific plague known as the Wailing Death.  As the story progresses, the real "bad guys" are revealed and a cure for the plague grows within reach.

The two expansions have some very different plots.  In Shadows of Undrentide, for example, you play as a student sent out to recover several stolen magical artifacts.  Your journey leads you from the Silver Marches, across the deserts, and finally to Undrentide where your goal resides.

In Hordes of the Underdark, the level cap is expanded to 40 (in original D&D, the maximum level is 20 but your DM may opt to modify the rules, of course).  The events in Hordes pick up where Shadows of Undrentide left off, leading your character into a massive subterranean area called the Underdark.

The stories are certainly above average, but not necessarily compelling enough to the point of playing 20 hours non-stop in one sitting like some other RPG's.