F.D.R. Martini after the American president Franklin Delano Roosevelt.
This drink varies from delicious to disgusting, depending on the liquid in your jar of olives. Oil will provide a revolting emulsion: make sure that your olives are packed in brine.
Substitute vodka for gin.
Some attribute the creation of this drink to Roosevelt: the 32nd President was a keen home bartender, although his cocktails were reportedly "horrendous" and there is no evidence that he used olive brine in his Martinis.
Also see our Dry Martini page.