An ancient Vulcan pagan festival of indulgence, not observed for a thousand years, which Neelix cheerfully proposes to revive aboard Voyager in order to provoke Tuvok.
Rumarie is a festival from Vulcan's distant past, before the reforms of Surak turned its people towards logic. It was an occasion of feasting and unrestrained revelry, and by the 24th century it has not been celebrated for about a millennium.
It is mentioned in the Voyager episode Meld. Neelix, who has made it his mission to coax a smile from Tuvok, announces that he has been reading about the festival and would like to hold one on the ship, complete with barrels of grease and unclothed celebrants.
The scene is played for comedy, but it sets up a darker one. After Tuvok's mind meld with the murderer Lon Suder weakens his control, he uses the holodeck to test himself against a simulation of Neelix at his most irritating, and strangles it.