No progressive dinner is complete without a wee aperitif, and this watermelon/tequila combo will serve the purpose admirably. You can prepare this in the morning and bring it with you in your cooler.
¼ cup water
¼ cup sugar
1 ¼ cups tequila (a good quality silver is best)
Juice of 2 limes
Generous handful blueberries
1 lb seedless, diced watermelon
½ cup fresh mint leaves
Bring the water and sugar to a simmer in a small pan, until the sugar is dissolved. Let cool. Puree the watermelon in a blender until smooth. Strain into a bowl and throw out the pulp. Combine the sugar syrup with the lime juice, blueberries and mint leaves; lightly crush the latter two with a spoon. Add the watermelon juice and tequila and refrigerate. Serve in tall glasses over ice, with a sprig of mint to decorate.