The thing about summer that I absolutely LOVE is that you can go home after a work day, have a rest, unwind, relax, and at about 9-9.30 pm get ready to go out and meet your friends for a late meal and drink, and the day is yet to begin!
This is what we did Friday night, by going to a lovely restaurant-bar that I like called "Leb-i Derya" (http://www.lebiderya.com/lebiderya/eng/1_2_index.html).
It's a nice place with a beautiful seaview, overlooking Istanbul... The service is good.
Hope we all enjoy the long days of summer...