Definitely one for the "kids of all ages" this month, with the Puppet Festival taking place in Poble Espanyol over the next two weekends. I find myself looking more towards activities for families or things for small kids more and more, so apologies for those expecting more party posts!!
Set in the fantatic location of Poble Espanyol up on Montjüic and only in its second year, the "Titelles Objectes Teatre" Festival welcomes puppet acts from around the world from the 18th to 27th March. There seems to be a fair variety of shows as well as productions going on for adults as well. Workshops for both children and professionals and something to cater for each agegroup.
Groups from Belgium, Iran, Israel and various parts of Spain tackle modern versions of Shakespeare, Carmen, Quijote, The Little Prince amongst others with Hip Hop Beatbox jam puppet sessions thrown into the mix. For a full programme of events, check the official site on the link above. It's also worth a mention that many places have discount tickets around (I picked one up in my local Bon Area supermarket, for example) with a great deal on the actual ticket prices. And I think there's still time to volunteer as a helper if you fancy it, instead.
If you'll be visiting the city this month, why not ditch the idea of the typical hotel and opt for a Barcelona Apartment instead? Some great savings can be made in groups or families.