Utumno is a single-player roleplaying dungeon adventure. Such games are often called "roguelike". It is very highly related to the game Angband, and somewhat less so to Nethack, ADOM, and (much more loosely) Diablo. Most such games are textual in nature. However, one of the eventual goals of the Utumno project is to provide a good graphical interface. Utumno is freeware with open source code to all. Some of it is based on the works of J.R.R. Tolkien, and it also bears a fairly good resemblance to AD&D.
Warning: all pictures below are old! Check back soon for some pictures of v1.0a5.
Here are some screenshots of v1.0a4. Click on each for the full-size version.
And here is that sample animated .gif I created to show what Utumno animation might remotely resemble: