The Moscow Mule is a classic cocktail traditionally made with vodka, ginger beer, and lime juice, served in a copper mug. Variations of this drink often include different spirits or flavorings. For example, a Mexican Mule substitutes vodka with tequila, while a London Mule uses gin instead. Other popular variations incorporate fruit flavors, such as the Berry Mule, which adds muddled berries for a refreshing twist. Additionally, some recipes may use flavored ginger beers or include herbs like mint for added complexity. These adaptations allow for a wide range of tastes while maintaining the original's refreshing essence.