Want to see Manhattan and Brooklyn by water? … Want an easy way to avoid the subway and traffic while doing so? Then take the water taxi!
New York Water Taxi offers a 2-day unlimited pass that is only $20 … see New York from the East and Hudson Rivers …
They have an excellent web site … interactive map with links to nearby tourist sites, restaurants, NextBus … and suggested walking tours … printable schedule (pdf)

Unlimited hop-on hop-off stops

• Hunters Point, Long Island City Water Taxi Beach
• East 34th
• Fulton Ferry Landing (DUMBO in Brooklyn) Brooklyn Bridge Anchorage | St. Ann’s Warehouse | d.u.m.b.o. arts center
• South Street Seaport
• Wall Street (Pier 11)
• Battery Park (Slip 6) Battery Park | Statute of Liberty | Staten Island Ferry
• World Financial Center (North End Avenue at Murray Street) Ground Zero
• Greenwich Village (Pier 45)
• West 23rd Street (Pier 63, Chelsea Piers) Christopher Street
• West 44th Street (Pier 84) Intrepid Sea and Space Museum | Times Square and Broadway | Jacob Javits Convention Center

NYWT offers other tours, but we recommend the $20 2-day pass or the two-hour $20 Sunset Cocktail Cruise.
Subway interactive map | schedules | HopStop
AGINY Good Value