I was in Barcelona on biz a few months ago, and you must try this little restaurant called OT!!

I went for lunch, but I imagine dinner is just as wonderful. There's no menu--just about 8 (small) courses which they choose for you. The menu apparently changes every day, but you have no choice in what you get. Fun!

No worries, though, they do ask if there's anything you don't eat before they start bringing things out....