For the watermelon ice cubes: In a blender, puree the watermelon with the Simple Syrup and lime juice. Pour into a silicone ice cube tray and freeze about 8 hours.
For the shandy: When the ice cubes are ready, cut a slight slice off the bottom of the watermelon so it sits upright. Carefully cut across the top quarter of the watermelon, leaving three-quarters left. Scoop out the watermelon with an ice cream scoop, reserving the insides for another use (or use to make the watermelon ice cubes). Cut a V-shaped notch in one side of the watermelon.
Put 4 watermelon ice cubes in the hollowed-out melon. Pour in the lemonade until it fills it about three-quarters full. Quickly immerse the beer bottle into the lemonade, leaning it in the notch and making sure the opening of the bottle hits the watermelon floor.
Yield:1 1/2 cups
Combine the sugar and 1 cup water in a small saucepan and bring to a boil. Cook, stirring, until the sugar dissolves. Remove from the heat and let cool completely. Keep covered in the refrigerator up to 1 month.