Years ago, when I regularly taught Spanish, I started collecting the most amusing mistakes made by my students and by those of my co-workers. Just as a lot of advanced-ESL errors in papers come from overreliance on the spellchecker, a lot of mistakes at the beginning Spanish level come from misuse of the dictionary -- mostly from using the wrong Spanish translation for an English homonym. (For example, in Spanish, the hole in the ground from which one take coal is a "mina"; the pronoun expressing that something belongs to me is "mío". In English the word for both is "mine".)
Here is my collection of the best (?) mistakes, previously kept on 3x5 cards, awaiting their day in the sun.
"Me gusta el estacionamiento porque es cerrar." [I like the parking because it is close.)
Local baseball team: "Columbus Tijeras de Podar" (Columbus Clippers) [From Daniel C.]
Regarding the need to wear warm clothes in winter: "porque puede dejar caer a bajos adolescentes a tiempos" (because it can drop to the low teens at times) [From Daniel C.]
"Deseo tener una familia grande con tres cabritos." (I want to have a large family with three kids.) [From Tim F.]
"El Salvador mentiras between Nicaragua and Honduras. (...lies...)
En Cuba la fiesta comunista gobierna el país."
"Mis tíos están construyendo una casa este caída." (...this fall)
"Los productos importantes de Argentina ... incluyen ... planchar." (...iron)
"La Ciudad de México es la mayúscula de México." (...capital...)
"Khadafi restos a grande." (Khadafi remains at large.) [From Jala P.]
"Fui a un raro." (I went to a bazaar [bizarre] -- in this case it's a homophone rather than a homonym.) [From Lisa W.]
More to come ...