Originated in Fontana, CA at the Autoclub Speedway Nascar Pepsi 500 Cup. Dolores, the bar patron, ordered a margarita on the rocks but the bartender immediately began making a bloody mary with Tabasco sauce. To avoid waiting, Dolores said to continue making the margarita in the same glass. The Dolores Margarita was born. It was a spicy and delicious margarita. The whole bar began ordering Dolores Margarita's shortly after.