Angband is a roguelike -- roughly speaking, a pseudo-RPG where in-game objects and creatures are represented by plain text characters. It is, I believe, the second-oldest still developed roguelike (bested by NetHack).
"Don't let the name fool you: The Unnamed Angband has no shortage of distinct flavour that sets it apart from any other variant. You adventure in Tolkien's world, through towns and wilderness and multiple dungeons, journeying from Bree towards greater and greater danger.
This variant roughly
... [More] doubles the monster list, expands the class-based system of Angband with numerous possible specialties that let you fashion a unique character, offers a positively absurd variety of terrain (cages that trap you, floor chests that can store objects, burnable woods, chasms, bloodstains), and includes a bunch of major interface improvements, including better presentation of graphics and an experimental isometric view." - From angband.oook.cz. [Less]
Tangaria – free open-source multiplayer roguelike game which combines the complexity of roguelike genre and social features of MMORPG: group PvE, PvP (on demand), housing, trading, anti-cheating mechanics and advanced real-time gameplay – game become semi turn-based when your character is injured.