Every Wednesday, there's a Blues Music Night, where relaxed Blues Music is DJed. If you want a relaxed night from your busy work, touristing, or you're just tired of the crazy Istanbul energy, come here and be comfortable. People come chat, have a drink, and even dance. :) Here's a sample of the music that is played:
http://www.youtube.com/playlist?list=PL36B556B76D886477

Name: Address Bar & Cafe (Santa Ottoman Hotel)
Join on Facebook: http://www.facebook.com/events/442724549139392/
Price: FREE

People attending from Facebook: 36 people.