The Art of the Pun--cultural or linguistic artifact?--Yo! Mary Anne!
I've never been able to figure out why, but the pun does not exist in Spanish. The closest thing to it is the double entendre, usually with a bawdy or burlesque connotation, just like it's sometimes used in English. Sometimes, a similar sounding word is deliberately misused in a speech to poke fun at the ignorance of the speaker, but the pun as we know it in English, as an almost abstract form of humor, an exercise in deliberate symbol distortion, simply does not exist. I wonder if the pun is a part of other languages, and if it's used the same way as in English.
There is also no word in Spanish for "pet". Spanish people keep pets, but there is no word in the language for them. The closest thing is "animál doméstico". Go figure.