A green mixed drink that Leonard McCoy brings to a dejected Captain Kirk in The Ultimate Computer, boasting that it is known from Earth to Orion.
Finagle's Folly is a cocktail prepared by Doctor McCoy in The Original Series episode The Ultimate Computer, set in 2268.
With the M-5 multitronic unit running the Enterprise and most of the crew put ashore, Kirk has been left with nothing to do, and a visiting commodore has addressed him as Captain Dunsel, Academy slang for a part that serves no purpose. McCoy turns up in his quarters with a tray and two glasses of a bright green drink, saying that it is called Finagle's Folly and is famous from here to Orion.
Kirk drinks to the captain's chair and quotes Masefield on tall ships. The name refers to the Finagle of the joking scientific law that anything which can go wrong will.