Baldur's Gate is a CRPG computer game originally released in 1998 by Bioware. It takes place in the world of the Forgotten Realms, using the d20 roleplaying system with turn based combat.
Critically acclaimed when it was first released, it is known as one of the best roleplaying games of its time. The storyline, while linear at times, is filled with intriguing side-quests and wonderful dialogue with the many and varied NPC characters, making the entire gaming experience an incredibly satisfying one.
You can have up to 5 NPCs in your party at any one time to accompany your PC on your quests, bicker among themselves, and generally provide character to your game. There are also different paths you can follow, that of good, neutral, and evil, to fully allow a breadth of different roleplaying experiences with each new game.
This game also has an expansion in the form of Baldur's Gate: Tales of the Sword Coast, which gives you several new areas to explore and have great sidequests in. And, of course, the story in Baldur's Gate continues in its sequel Baldur's Gate II: Shadows of Amn and its own expansion, Baldur's Gate II: Throne of Bhaal.
You grew up as an orphan in the isolated fortress of Candlekeep, your only link to the past being your foster father Gorion and your foster sister, Imoen. Your sheltered existence is shattered, however, when one morning Gorion summons you to his room and says you will be leaving Candlekeep this very day. After giving you money to buy equipment, you are thrust into the world from your home as Gorion is slayed by a mysterious armored character, with Imoen and the knowledge that the entire expanse of Faerun will soon be open to you under the most intriguing and secretive of circumstances...
Baldur's Gate is relatively moddable with the addition of WeiDU (Weimer's Dialogue Utilities), but most modifications are made on the easyTuTu, BG1TuTu or Baldur's Gate Trilogy platforms. These platforms allow you to play Baldur's Gate with the newer and better engine that comes with Baldur's Gate II.
This expansion offers several new side-quests and areas, including the new town of Ulgoth's Beard, an expansive dungeon in the form of Durlag's Tower and an entirely new island. You can journey to these additional places with your friends from Baldur's Gate I during the game itself. It also updates the interface, making gameplay simpler and more intuitive.
Tales of the Sword Coast also adds multiplayer capability to Baldur's Gate, allowing up to 6 people to play online, via a LAN or via TCP/IP.