Mountain Dew(R) and tequila = Margarita in this recipe! So simple you'll wish you had thought of it first.
This is the original recipe as near as I can tell, and if its not, it is as far in the search as I need to go. As a warning, however, this does go down smooth, but it is not for the timid.
We used to make these in the dorm and invite a group over. Makes about 1 pitcher. We had to limit everyone to 2 at first since it would tend to hit when we thought it wouldn't. If you're really brave try to play beer pong with it.