I chose to go to a flamenco show in Barcelona, even though I had read that it wasn't from that area. We had a free night and no time to see a show in the south (most tourists are not going to travel to the south to see a show anyway, so ignore what that opinionated a hole above said, he wrote some crappy stuff on a question I asked prior to visiting last summer, he is usually very offended and doesn't want money to help to stimulate his country's economy). The show was wonderful, the Sangria was wonderful as well.
Do: see Sangrada Familia and Guadi's other works (this will also give you a little background on the Catalan culture, these people do have their own cultural identity and it is interesting to pursue). Do: look at trip advisor and find a great restaurant to eat at, had the best meal of my entire trip there. Do: take a day-trip wine tour and learn about Cava (made the exact same way as Champagne, but unable to be called Champagne). Do wander through the gothic quarter. Maybe: the beaches were okay, but the beach in Sitges to the south was amazing. Don't: do Montserrat, it was a tourist trap and miserable with huge lines.
The public transportation was great in Barcelona and they had rental bikes as well. Have an amazing time!
Yes, watch a football game at the huge Nou Camp stadium, home of the best team in the world nowadays: FC.Barcelona, Bar?a for short.
Worst thing to do in Barcelona: attend a flamenco show, as this is music from Andalusia in Southern Spain and in Barcelona we are Catalan and have a different culture, language and identity. Also: don't drink sangria. This is a vulgarity we locals never drink, only foreing tourists do because they think it's typical.
watch fc barcelona games! thats if you like soccer
Enjoy the food. The seafood is particularly fresh.
Explore the old city on foot.
drink sangria
