Cinco de Mayo is the Fifth of May. "They" say it's Mexican Independance Day, but it's actually something else. I can't remember what, but I think someone mentioned it earlier in this thread. Regardless, that's all story. In the US Cinco de Mayo is an excuse for everyone to be "Mexican", get totally smashed on Coronas and Cuervo margaritas, and exhibit absolutly no intelligence. Oddly enough, jails and drugstores are filled with hung over drunks the next day.