¡Todos a sus puestos!
UC3M's orchestra holds auditions in mid-September and meets once a week, on Saturdays, at the Leganés campus. The first concert in the fall is held at the end of October at a small hall in Leganés, though for the second concert, usually at some point in late December, the orchestra travels to Toledo or Segovia.
Although the orchestra is not a huge time commitment, I found that the experience was extremely rewarding. Manuel Coves, the conductor, is easy-going and remarkably accomodating. I never once felt left behind or confused because I am not a native speaker. I owe this, too, to the other members of the orchestra, who were always there when I had a question. Some of the members are students, some professors, and some are musicians from the community.
The repertoire was diverse, if not as challenging as what I have come to expect from working with Vassar's orchestra. For the first concert, Manuel chose a selection of Spanish music, ranging from a short collection of classical Spanish dance music to a contemporary concerto for accordion. To get a better idea of what the orchestra plays, check out some of their previous concerts (many of which are on YouTube).
Overall, I highly recommend UC3M's orchestra as a cultural activity. Be sure to get in contact with Manuel Coves, email@example.com, before the end of September (or the end of January, in the spring term).