The vibrant city of Barcelona, the capital of Cataluña is a very popular short break destination. It has interesting architecture both modern and old (many examples of the modernist architect Gaudí can be seen here), museums, art galleries and theatres, the amazing Sagrada Familia church and of course the shops, restaurants and numerous tapas bars. We don't recommend taking a car into the centre as it is notoriously difficult to park, but you can easily get about on the metro, which is quick, cheap and efficient, or probably the best way to get to know the city is by walking.
A short trip outside of Barcelona is Montserrat, famed for its monastery and declared a conservation area by UNESCO. You can take the funicular (cable car) up there where you can enjoy spectacular views.
Just inland from Barcelona lies one of Spain's most important wine producing regions and this is where Cava (Spanish champagne) is produced. There is an excellent wine museum in Vilafranc del Penedés where you can taste the wines (but it's closed on Mondays).