The poster on the Palace of Fine Arts says... "Today only, 9 P.M."
The street musician's sign says... "Daily at all hours."
"It is true that Aztec heart-removers ("sacacorazones" is a play on the word "sacerdotes"... priests.) were the first Mexican cardiologists."
The priest is asking for an obsidian knife instead of a scalpel.
Here are a couple that deal specifically with the subway...
A rather universal criticism of our modern world.
Everyone is so absorbed with their cell phones that can't be bothered to give their seat to the little old lady.
The gorilla asks the subway driver "Are you passing by Chapultepec?"
(Chapultepec Park is where the zoo is located.)
The humor may fall flat in translation, but they gave me a chuckle, and Alejandro laughed out loud when I showed these to him.