1 large can frozen limeade
1/2 cup tequila
1/4 cup triple sec
A little sugar if desired
Put into electric blender and fill blender with crushed or small cubes of ice.
Blend until smooth and frosty.
Put margarita salt (kosher salt works just as well) on a paper plate. Take a slice of fresh lime and coat the rim of a glass, then turn the glass upside down and coat the rim in salt on the paper plate. Fill with margarita and last put the slice of lime of the edge of the glass.
Non-alcoholic version: Substitute Sprite for tequila and triple sec. Use more sugar and a splash of lime juice to increase flavor.