The Garden of Immortal Peaches

• 3 cups seedless-watermelon chunks (about 1 lb. peeled watermelon)
• 1 ½ cups fresh lime juice
• ½ cup sugar (or less, to taste)
• 1 cup tequila
• ½ cup Grand Marnier

Combine watermelon, lime juice and sugar in a blender, and blend on high until completely liquid and frothy. Combine in a pitcher with tequila and Grand Marnier. Fill pitcher with ice, stir and serve.

BTW: Ice goes in at the last minute, so it doesn't dilute.