Hodjapasha Art & Culture Center is a restored Ottoman hamam (Turkish bath) in Istanbul's Sirkeci district (map) now used for performances of the Mevlevi (whirling dervish) sema, Turkish folk dances, and belly dance.
The restoration work is well done. It's an intriguing space with good acoustics and lighting, right for the mood of the performances. (Unfortunately, the ancient building cannot accommodate wheelchairs.)
This is not, strictly speaking, the full sema (religious service). It has been shortened to one hour, but it is an authentic representation, and you certainly experience the gravity and mystery of the sema.
It starts with a short (about 10 minutes) concert of Ottoman classical music. This is a secular performance, and applause is allowed, but applause is not appropriate after this, for the rest of the evening.
The sema is not a show, but a religious observance.
The musicians leave the stage, and soon return dressed in their Mevlevi dervish robes. After them, slowly, solemnly, the dervishes enter. Prayers are chanted by the hafız. The dervishes whirl four times for 10 to 12 minutes each time.
The final whirl ends with just a single instrument playing, then silence as the dervishes continue to whirl. A final prayer, and the slow retreat of the dervishes ends the sema.
Hodjapasha Art & Culture Center also hosts performances of Turkish folk and belly dance on Tuesday, Thursday, Saturday and Sunday evenings at 21:00 (9pm). I'm not usually enthusiastic about "nightlife" shows, but I thoroughly enjoyed this high-quality performance. Complimentary refreshments are served during intermission. An exhibit in the foyer outlines the 10,000-year history of dance in Turkey.
Take the Bağcılar—Kabataş Tram from Sultanahmettoward Eminönü or Kabataş to the second stop (Sirkeci), then walk south up Ankara Caddesi (away from the Bosphorus) to tiny Hocapaşa Hamamı Sokak on the left (map). Walk along this street, which turns right, and the Art & Culture Center is on the left.