I had some extra yellow watermelon from CSA Week #8 so I puréed about 4 oz. of watermelon into a frozen margarita:
4 oz. watermelon (seedless, or seeds removed)
1.5 oz. Sauza Hornitos tequila
0.5 oz. triple sec
1 oz. lime juice
0.5 oz. simple syrup (sugar and water)
ice
Blend the ingredients together. Serve in a salt-rimmed glass.
Very refreshing!