This is one of the great ways to get a bird's eye view of Barcelona. The cable car cuts across the entire harbor and directly to Montjuic. It's probably mostly for families and children, but don't knock it - you'll get a great impression of the city.
It's a great way to get from the beach to go exploring on Montjuic - it's quick, though pricey compared to a metro ticket. But then again, just dangling in the cable all the way up is the whole experience. Tickets are 9 euros single, 12,50 return. There's a restaurant on top of the cable car tower.
Come out early to dodge the worst crowds.
Mon-Su: 11:00-17:30