The Unreal World

Another Roguelike. This one is very indepth, and includes many different features that make it involving to play, such as the huge variety of classes, locations, seasons, etc. It has an emphasis on "northern folklore" (particularly that of the author's native country Finland) rather than the purely fantasy theme of most Roguelike games. Personally, I still prefer Nethack, even though the graphics for URW seem pretty good (for a Roguelike). Check it out if you're a fan of long, involving RPGs. This game is still under active development, and versions for modern operating systems can be found on the official website.