A crazy mod team has spent seven years recreating Baldur's Gate in the Neverwinter Nights 2 engine. Not parts of it -- the whole thing. They didn't just start, either; it's done and it took seven years. Yup, it's crazy. It's also really awesome.
Baldur's Gate: Reloaded goes way beyond Baldur's Gate: Enhanced Edition and previous mod attempts to bring the classic role-playing game into the modern era. It recreates the entire game in 3D. You have to have Neverwinter Nights 2 and all of the expansions to play this, but you can grab that from GOG.com for twenty bucks. Then you'll have more RPG than you know what to do with.
[Update: Users have reported that this will not work with the Steam copy of the game. You can't buy it anymore off of Steam, but if you already own it you won't be able to use this mod.]