Try Rirkrit Tiravanija's recipe for his version of Negroni cocktail.
Rirkrit’s Negroni recipe appears in the book Rirkrit Tiravanija: Cook Book – Just Smile and Don’t Talk published in conjunction with an exhibition of the same name at Kunsthalle Bielefeld in 2010. The book contains a collection of 23 recipes for a variety of dishes, ranging from Pad Thai to Flaming Morning Glory.
Rirkrit doesn’t deviate from the classic Negroni recipe which consists, essentially, of equal parts gin, Campari and sweet vermouth, with a slice of orange. He does helpfully specify his favourite brands. His Negroni is made with Bombay Sapphire Gin, Cinzano Campari and Martini & Rossi sweet Vermouth and he suggests substituting a blood orange for the regular orange when it is in season.