Dungeon Crawl Stone Soup
Dungeon Crawl Stone Soup is a fun, free rogue-like game of exploration and treasure-hunting in dungeons filled with dangerous and unfriendly monsters in a quest for the mystifyingly fabulous Orb of Zot.
Dungeon Crawl Stone Soup is a variant of Linley's Dungeon Crawl that's openly developed and invites participation from the Crawl community.
Dungeon Crawl has superb, deep tactical gameplay, innovative magic and religion systems, and a grand variety of monsters to fight. Crawl is also one of the hardest roguelikes to beat. When you finally beat the game and write your victory post on rec.games.roguelike.misc, you know you've achieved something.