Catalan Christmas Concert at the Palau de la Música
Every year in Barcelona, the city's great choral society -- the Orfeo Català -- puts on a Christmas concert on the 26th of December, Sant Esteve, which is also a holiday. If you spent Christmas with your family, then you will probably spend Sant Esteve with your in-laws.
The concert takes place in the great modernist (Catalan art nouveau) concert hall, the Palau de la Música, and all the different choruses of the Orfeo Català, children, chamber, adults, etc. participate. This year's concert was one hour forty minutes in duration. It was shown live on Catalan public television and here is a link to the video (which will begin with one or two advertisements, but have patience). One song will run through the concert, the Catalan classic Fum, Fum, Fum. And if you pay attention, you will see various members of the choruses wearing (of their own accord) yellow ribbons to remember the Catalan political prisoners imprisoned in Madrid.
If you don't want to watch or listen to the whole thing, you can watch this two-minute video of the finale, El Cant de la Senyera. It's not the national anthem, but it is an anthem dedicated to the Catalan national flag. And it is very beautiful