Triple sec is an orange-flavored liqueur and is a common ingredient in sweet or tart cocktails including the Margarita, Cosmopolitan and Kamikaze. Some people also opt to drink triple sec plain, either neat or on the rocks.
A basic Margarita requires 1 to 2 ounces of tequila, 1 ounce of triple sec and between 1/2 and 1 ounce of lime juice. Adjust the amounts of tequila and lime juice to taste, and serve the drink over ice or blended with ice in a Margarita glass with a salted rim. Add fruit such as frozen berries to a blended Margarita to increase its sweetness.
DrinksMixer.com lists a Cosmopolitan recipe that calls for 1 1/2 ounces of vodka, 1 ounce of triple sec, 1 ounce of lime juice and 1/2 ounce of cranberry juice. Combine the cocktail ingredients and ice in a cocktail shaker. Shake the drink vigorously, and strain it into a martini glass.
A Kamikaze is essentially the same drink as a Cosmopolitan, but without the cranberry juice. Combine 1 ounce of vodka, 1 ounce of triple sec and 1 ounce of lime juice in a cocktail shaker with ice, and strain the drink into a martini glass.