Turducken: A three-fowl dish consisting of a turkey stuffed with a duck that has in turn been stuffed with a chicken. (All three birds are first de-boned.) Turducken is "believed to be Cajun in origin," according to this Wikipedia article, and is popular at Thanksgiving feasts, but not as popular as turkey stuffed with bread or other grain-based dressings.
Barry Popik has determined that the first published mention of turducken was in 1982. Be sure to read Popik's entire article for much, much more on turducken (including the trademark record), as well as notes on churkendoose, chuckey, churkey, qua-duc-ant, osturducken, and turduckencorpheail (turducken stuffed with Cornish hen stuffed with pheasant stuffed with quail).
Photograph: Hinck Turkey Farm.