No Budget: The studio's annual operating budget is about US$35,000; for a game that's coded by one guy and which started out as a pure hobby project, that's pretty high. For a game that's won a large stack of awards, spawned at least three or four imitators from much larger and better-resourced studios, been the subject of a feature article in the New York Times, and now appears as part of an exhibit in New York's Museum of Modern Art, it's astonishingly low.
"Dorfs" for dwarves, "Dorf Fort", "Urist McX" for any given dwarf, "Cutebolds" for kobolds, "Hidden Fun Stuff" for gateways to hell.
"Cotton Candy" for adamantine, "Clowns" for demons, and "The circus" for hell.
"Party People" for ghosts, due to a rather infamous incident.
"Goblinite" or "Goblin Christmas" for the vast bounty of meltable iron weapons and armors a Goblin Siege would bring, once your forces had killed them. No longer the case as of DF2010, however, as they now use mostly leather, and frequently use lesser metals for their weapons and helmets.
"Zombie Spirals" for a common occurrence when the player embarks in an evil biome that raises everything as undead. The more that get killed, the more undead there are to fight, until your dwarves are completely overwhelmed.