Dungeon Crawl Stone Soup is an open-source, single-player, role-playing roguelike game of exploration and treasure-hunting in dungeons filled with dangerous and unfriendly monsters in a quest to rescue the mystifyingly fabulous Orb of Zot.

DCSS is based on Liney's Dungeon Crawl, but has been modified drastically since the project began. Thousands of new features and bugfixes have been added over the years, and the game continues to grow with a very active development community.

Source: Game's Website.