You can rent a boat. It costs $ 15 per hour and each boat has capacity for 4 people. Another option – quite romantic – is to take a gondola ride! The gondola holds up to 6 people and one of the gondoliers is Brazilian, Joseph Gama! It costs $50 for half an hour plus tips. More infos here.You can make your reservation by phone (212.517.2233) or try to contact them by the form.