1/2 c. water, boiling
3/4 c. sugar
4 c. ice, cubed
1/2 c. lemon juice
4 oz. tequila or lemon vodka (optional)
Mix sugar and boiling water, cool to room temperature in fridge or freezer. Add ice to blender and crush. Add lemon juice, sugar and liquor and blend. Scrape down sides of blender. Blend until smooth. Serve with salt- or sugar-rimmed glasses.