I took my two daughters to Barcelona at half term. We tried not to stick to the obvious tourist agenda but explored markets, back streets, vintage clothes shops, bookshops, small cafés, gardens and the beachfront. We liked Gaudi's mosaics but we aslo liked the grafitti, especially around the university. 
Our recommendations for anyone visiting Barcelona are...
Best places to shop: the Mercat de la Boqueria on Rambla de Sant Josef, for food; and the streets just behind, between the market and the Museu d'Art Contemporani for beads, jewellery findings, clothes and accessories, particularly Curtidos Pinós, 79 Carrer de l'Hospital, which sells leather thongs and bands in every width and colour. There's also a big flea market, Encants, selling new clothes and furniture as well as antiques, books and lots of real tat – plus a few treasures! It's a few blocks east of La Sagrada Familia, and open every Monday, Wednesday and Friday.

Best places to eat: two restaurants, both in the same street (nearest Metro station: Passeig de Gracia). Madrid e Barcelona is more intimate and cosy and La Rita is lighter, brighter and more bustling, but they both serve great Catalan food and the prices are very reasonable.
