prepare glasses with salted rims. in a large pitcher, add the frozen limeade concentrate. do not add water! using the empty juice can, fill with beer, add to the pitcher. (cheap beer works just fine here) then, again using the juice can, fill with tequila, then add to the pitcher. mix well, until frozen limeade is no longer in lumps.
fill blender about halfway with crushed ice. add some of the beer/juice/tequila mixture to just cover the ice, and blend until well slushy and there are no more big ice chunks. pour into the salt prepared glasses. repeat until everyone has a drink! makes about 4 to 6 drinks, depending on how big your margarita glasses are...i have a pair of margarita glasses that takes half a blender to fill! (the unused portion of mix can be frozen for later use)
these make fairly kick-your-butt strong drinks. (if you like, you can half the amount of tequila, but where's the fun in THAT!)