As any city near a waterway, Budapest has always had a special relationship with boats. Before bridges were built across the river, the crossing was made by boat- it seems quite strange to think, while casually strolling over Margit bridge, that in the past people had to queue and pay to be able to make it to the other side and payment of tolls was maintained on the bridges too at first. Now boats are used mostly for sightseeing, Budapest Transport Ltd has a boat connection between Soroksár and Csepel, and Mahart has boats going all the way to Vienna, but you can also invest in some shorter trips, to Szentendre or Esztergom. (http://www.mahartpassnave.hu/webset32.cgi?MAHART@@EN@@32@@6215319 ). Many boats moored to the docks never budge- they are used as restaurants, clubs or bars and here on Újpesti rakpart you can even rent offices on boats.