Barcelona Recommendations
Some of my friends asked for tips, I don't live in Barcelona but visited multiple times and enjoyed these things, publishing this for future reference, in case you find it useful.
Barcelona is great at any time of year. Summer can get pretty hot and busy. I don't know many places but can share some of the stuff I enjoyed.
Be smart with your belongings to avoid pickpockets.
Stroll around Ciutat Vella (old town). We had a lunch menu del dia at El Reloj (not sure if it's good at different times of the day), but we had good service, good food and it was affordable at ±€20/person. It's a 10 min walk from Arc de Triomf.
Montserrat is definitely worth a visit if it interests you. Leave early. You can rent a car for cheap, around €30 per day (we went with our car) but it looks like you can also go by train.
Museu Nacional d'Art de Catalunya is nice and free and has a great view.
Still have to go, but my wife is really excited about this museum of banned art.
Also check out the Olympic stadium - there's a nice park and viewpoint nearby.