You know how, in a most offices and institutions, if there's a breakfast event, people will bring bagels, doughnuts, or pastries? When I was planning to move to San Antonio, someone from here told me that here, people will bring breakfast tacos instead. I was skeptical--that is, until my boss showed up one day my second week with a big bag of breakfast tacos. This happens about once a week.
Also, just about every other restaurant here is Mexican, and just about every Mexican place (and some non-Mexican places) sell breakfast tacos. A breakfast taco is basically a (usually) freshly made soft flour tortilla, usually with two of the following: eggs, chorizo, potato, bacon, cheese, or beans. They can be pretty tasty.
According to this article in the Denver Post, San Antonio is the birthplace of the breakfast taco.