Hamams:
A visit to a hamam (Turkish bath) is an essential part of any trip to Istanbul and is something you'll be sure to repeat before leaving. There are at least one historical hamam in each neighborhood of Istanbul. Take care in selecting a hamam, as they can vary greatly in cleanliness. Most places will offer a scrubbing and/or a massage. Just being in the Hamam (as a sauna), is enough for seeing and experiencing the place, but the scrubbing is a great experience. The massage is not necessarily better than those found in western countries.
Sultanahmet has many historical hamams. Some are very extravagant and cater mainly to tourists.

Nargile (Hooka/Water Pipe):
Once upon a time, the nargile, or Turkish water pipe, was the centre of Istanbul's social and political life. Today some of the locals still consider it one of life's great pleasures and is something interesting to try. Most of the places where you can smoke a nargile are in Yeniçeriler Caddesi, near the Kapali Çarsi (Grand Bazaar). Çorlulu Ali Pasa and Koca Sinan Pasa Türbesi are both in secluded internal courts, just around the corner from some tomb yards, while Rumeli Kahvesi is actually inside the cemetery of an old medrese, though it's not as spooky as you might think. In the south of Sultanahmet, near the sea, is Yeni Marmara (Çayiroglu Sokak), where you can also sit in the terrace and enjoy the view. In Beyoglu, at the Ortakahve (Büyükparmakkapi), there's even the choice of a wide range of flavors. Another area with few big good looking places is the Rihtim Caddesi, between Galata bridge and Istanbul Modern Museum.

The Classic Bosphorus Cruise:
From the terminal immediately east of the Galata Bridge starts the large ferry cruising to Anadolu Kavagi at the northern entrance of Bosphorus to the Black Sea via various stops. The fare is TL 25. The departure time is early and is very popular, so arrive early and queue. The open decks are hugely popular, so unless you have an outside seat expect people to be standing all around you constricting the view. The ferry waits some hours in Anadolu Kavagi so as you alight you are confronted by a numerous restaurants and their spruikers. Firstly take the walk to the Yoros Kalesi, a strategic castle overlooking and controlling the entry to the Black Sea. This important fortification with a commanding view has been fought over for many years and was last in use in the 19th century. It has fallen into serious disrepair, but Christian engravings are still visible in the stonework. There are restaurants actually in the castle surrounds and naturally have spectacular views. There is plenty of time left to wander back to the village for lunch. It is late afternoon before arrival back at Eminonu, but a day well spent. A cheaper and faster Bosphorus cruise alternative is a TL 10 trip on a shorter cruise.