The Cable cars. There are 2 great cable car rides in Barcelona - one from just next to the Miro foundation and Greek theatre on Montjic which takes riders all the way to the summit of Montjic with the old castle and some amazing views of the port and the old town. The other leaves Miramar, a lookout, and goes all the way across the water (usually over the top of the odd cruise ship) and down to Barceloneta beach. Either one is a great trip for the kids, and queues are usually tolerable and entertaining whilst you view the comings and goings of fellow tourists