This one is found all over Mexico... fizzy, refreshing and perfect for a summer party. In a cocktail shaker with ice add:

1 1/2 ounces tequila (use your favorite. I like a reposado for this drink)

1/2 ounce fresh lime juice

1 ounce grapefruit soda (sub Fresca or something if you can't find the grapefruit)

Shake well, pour, enjoy!