Aquí Hay Gato Encerrado
Literally, "there's a trapped cat here." Figuratively, there's something fishy going on.
Esos Son Otros Veinte Pesos
Literally, "that's another twenty dollars." The American alternative would be "that's a whole new ballgame," or in other words, a different issue entirely.
Juan del Pueblo
One of my favorites. Literally, "John from Town." English equivalent: Joe Blow.
Llamar Para Atrás
Those of you who know Spanish will get a kick out of this one. The literal translation would be "to call backwards," but it just means to call someone back.
A slangy way of saying "no way" (most likely an extremely cut down version of "ni para nada," which means not for anything).
Por Allí Para Abajo
Good to know if you're driving around and are thinking of asking for directions. The literal translation of this phrase is confusing: "Over there straight down." It just means straight ahead.
Ser Como Jamón del Sandwich
I love this one as well: the literal translation is "to be like the ham in the sandwich," but its English equivalent is to be the third wheel in a social situation.
Talk about misleading ... this looks like it means "being a patriot," right? Quite wrong. It's actually a rather base way of admiring a woman with large breasts.
Tomar El Pelo
Literally, "to take someone's hair." English equivalent: pulling one's leg.
One of the most popular sayings you'll encounter in a conversation with a local, tú sabes, along with ya tú sabes is literally "you know." As in, "That beach is the best, you know."