Now that I've lived in Mexico for over two years, here's some culinary discoveries I've made.
Coctel de camarones (shrimp cocktails): Shrimp and avocado in a spicy red sauce. I've learned that the difference between the good ones and the not-so-good ones is, the not-so-good ones are made with ketchup. The best ones I've found in Guanajuato are from Mariscos Los Amigos in Embajadores Park (see picture). The best one I've found in Mexico was in the Old Town of Mazatlan.
Cerdo (pork): There's something that they do when they cook pork that makes it melt in your mouth. I've heard that they use lard, which can't possibly be good for you. My preferred method of ingestion is in a torta (Mexican sandwich). This yummy picture was taken at the Mercado Hidalgo in Guanajuato.
Pozole verde: Pozole is actually hominy, but what we're talking about here is a soup that includes (usually) chicken, hominy, and some unknown spices, garnished with onions, lettuce, and radishes. It never tastes the same way twice, even when prepared by the same cook. There's also pozole rojo, which I don't like as much, and pozole blanco, which I haven't tried yet.
Torta Cubana: Something that you order if you're especially hungry. You could call it a torta with everything on it; chorizo, ham, slices of hot dog, yellow cheese, lettuce, and tomato. Incidentally, I recently spent two weeks in Cuba, and didn't see torta cubana on a menu once. This picture was taken at Tortas Mi Lugar at Positos 11 in Guanajuato.
Elote (corn on the cob): As sold by street vendors, it's corn with grated cheese, mayonnaise, chili powder, and lemon. You often get a choice of medium or asado (well-done). You can also choose whether you want an actual cob on a stick, or de-cobbed corn in a foam cup (vaso). I've always taken the vaso option, because I don't want to wear it. I also tell them to hold the mayonnaise.
Tripe: Not something worth writing home about, but it's listed here because there's a funny story that goes with it. The first time I tried it, I saw it being deep-fried by a sidewalk vendor, and my reaction was “umm, calamari; I love calamari.” Well, I learned about three days later that tripe isn't calamari; it's sections of cow intestines. Had I known this, I never would have tried it. Having tried it once, I like it OK. However, you never see tripe on a menu in a restaurant. It's always sold by sidewalk vendors; if you see it cooked before your very eyes, you know that it's cooked sufficiently. This picture was taken at Embajadores Park in Guanajuato.