Okay, I think I get it. Because ayuntar means "to join" or "to meet," I see how it could be taken either way. Similar to the word intercourse in English, which originally meant "discussion" but has come mean "coitus" in most every case. Also similar are conjugation and union.
Spanish definition of ayuntamiento: 1. Acción y efecto de ayuntar o ayuntarse. 2. Corporación compuesta de un alcalde y varios concejales para la administración de los intereses de un municipio. 3. Casa consistorial. 4. Junta (reunión de personas para tratar algún asunto). 5. Coito.
(My 'macaronic') English translation of that: 1. Action or effect of 'ayuntar' or 'ayuntarse'. 2. Corporation composed of a mayor and several town councillors for the government of a town. 3. Town hall (or city hall). 4. Meeting, assembly. 5. Coitus.
Murcielago is the Spanish word for bat. (I assume its etymology stems from the Latin words for 'blind mouse'). Apart from finding it a cute word to say, for many weeks this was one of my favorite words because - so I was told - it was the only Spanish word to contain all 5 vowels. It was only two days ago that I figured out that this last piece of misinformation was false, as I read some boring article about corruption in the ayuntamiento (local government) in Madrid. I don't find the word ayuntamiento nearly as much fun to say, however.