Crème de Cassis
From Wikipedia:
Crème de cassis (pronounced [kʁɛm də kasis]) (also known as Cassis Liqueur) is a sweet, dark red liqueur made from black currants.
Several cocktails are made with crème de cassis, including the very popular wine cocktail, kir.
It may also be served as an after-dinner liqueur or as a frappé.