Islamic Cairo is definitely not the place for alcohol. Rather, settle down for some tea and shisha.
Fishawy
In the street just behind Midan Hussein, Khan al-Khalili
For many years this was the preferred place of Nobel winner Naguib Mafhouz to meet with his friends. It's a great place to stop for tea and shisha and watch the world bustling by. Few places are better for having an easy conversation with people from all continents, as well as with relaxing Egyptians that speak English well.
Hotel Hussein Restaurant
Stay away from the food at this top-floor restaurant, but sipping a cup of tea above great views of the Midan Hussein by night is an enjoyable way to pass the time.