Calle Genova
Closed off for pedestrians and lined with bars, this street is basically one long pub crawl, spanning several blocks and all kinds of different establishments. You’ll be approached with menus by the hype people for various bars as you walk; feel free to take a quick look and move on to the next option if a place doesn't interest you (they're used to it). La Terraza and Bukowski's Bar are particularly good for people-watching and drinks, although you're better off looking elsewhere for dining.