The act of purchasing the "Grande Meal" consisting of 10 tacos, to be made up of 5 hard shell and 5 soft shell tacos, and consuming every last shred of each taco within a half hour. The rules are simple:
1) Eat EVERYTHING. This includes every shred of lettuce.
2) Choice of Border Sauce and drinks is left to the Challenger.
Everytime they got drunk, the Taco Bell Challenge was called for at around 2AM.