After breakfast or coffee at or near your hotel, it's time to head to a completely different part of the city – downtown. Take a train or cab down to Wall Street, which runs east from Broadway down to South Street. Though you can no longer enter the New York Stock Exchange building, it's an impressive site from the outside, as is Federal Hall (and don't miss the Charging Bull sculpture in Bowling Green Park).
After admiring the historic architecture of the financial district, walk east down Pearl Street to the cobblestone lanes of the South Street Seaport (Fulton and South Sts., Pier 17), once New York's shipping center between 1815 and 1860. Now a mixture of touristy shops, restaurants and bars, it's still worth seeing for its collection of historic ships, maritime museum and outdoor summer performances. Grab a bite to eat at one of the many restaurants within the Seaport, or for something a little more inventive, try one of the places in the blocks around the Seaport, such as Nelson Blue (235 Front St., at Peck Slip, 212-346-9090), which features hard-to-find New Zealand cuisine, or the historic (built in 1794) Bridge Café (279 Water St., 212-27-3344).
If you happen to be near the South Street Seaport on a weekend between April 26 and October 12, you can take a water taxi over to the Fulton Ferry Landing in Brooklyn – a wonderful way to tour the harbor for very little money. See www.nywatertaxi.com/hop for current schedules.
If the ferries aren't running or you'd like a little exercise, you can walk off that lunch with a stroll across the Brooklyn Bridge. It takes about half an hour to cross the bridge into Brooklyn – and longer if you stop to ogle the fabulous views of Manhattan's and Brooklyn's shorelines. Once you reach Brooklyn, head toward the water until you hit the Brooklyn Promenade, another amazing vantage point from which to see the tip of Manhattan. Spend some time enjoying the scenery before strolling past the old mansions of tony Brooklyn Heights.
When you've worked up an appetite again, stop for dinner at the renowned River Café (1 Water St., 718-522-5200), a ritzy place with classic food that's worth it for the beyond-breathtaking view of downtown Manhattan. For something a little lighter on the wallet, order a pie at famous Grimaldi's pizzeria. If you still have room after dinner, try an ice cream cone or sundae from Brooklyn Ice Cream Factory (2 Old Fulton St., 718-246-3963), thought by some to have the best homemade ice cream in all of New York.
Either walk back across the Brooklyn Bridge toward Manhattan to view the city lights, or take a train or cab back over. If you feel up for it, check out some of the trendy clubs and bars in the Lower East Side. The Living Room (154 Ludlow St., 212-533-7235) is always a good bet for local music in a cozy atmosphere (Norah Jones used to play here before she made it big).
After a day taking a break from seeing art, it's time to hit another one of the big museums. Choose between the Whitney (where you can grab a quick breakfast at the restaurant Sarabeth's, located in the lower level) and the Guggenheim, depending upon which has an exhibition that strikes your fancy (look up the current ones on the museums' websites before you go) or what's open that day (the Whitney is closed Monday and Tuesday; the Guggenheim is closed Thursday).