At peak times, it's standing room only in this jovial basement tapas bar catering to locals and students. The floor may be littered with napkins, and you might have to shout to be heard, but it's the generous tapas and big, sloppy bocadillos (sandwiches) that draw the crowds. (There's a dining room in back for which you can make reservations, but the bar is the place to be.) Although paella is usually the exclusive domain of pricey restaurants devoted to the specialty, you can enjoy a ración of paella during lunch here, ladled out from a large caldero (shallow pan). Another bonus: even if you just order a drink, you'll be served a liberal helping of the "tapa of the day."