For those that don't know, this year Monday, Sept 24th is La Mercè in Barcelona. From what I have read, its a local holiday and is the largest annual festival the city holds. Sounds like like the whole city livens up a notch for it and it pretty much takes over the historic distric, Ciutat Vella (I have noticed most of the events seem to be between Las Rambles and Via Laietana - Area 1 on this map: http://www.barcelona-on-line.es/mapa/index.htm and AKA the "Gothic Quarter"). Everything I read puts it as a "must see", so it may be worthwhile to extend your stay a bit if you can swing it. Unfortunatly, hotels are absurdly priced on Sun/Mon.
Here are some links:
http://www.buzzle.com/editorials/10-5-2005-78177.asp
http://www.barcelona-tourist-guide.com/en/events/barcelona-la-merce.html
http://www.spanish-fiestas.com/barcelona/festes-merce.htm
pictures:
http://www.barcelonagallery.com/eng/menu0%BF3.htm
official site:
http://www.bcn.cat/merce/_/
See ya in September!
-Ben

The new Mercè 07 poster and
The new Mercè 07 poster and site is out:
http://www.bcn.cat/merce/catala/home.shtml
Paco