j'ouvert is the party before carnival in Trinidad. It's the early morning "beginning" of the 3 day bachannal. J'ouvert is a french term meaning "day open." It is a fete where you cover yourself in mud/oil/anything and just party like there's no tomorrow.
Aye allyuh goin j'ouvert in de mornin? Steups, i done tired from de fete last night!