Khan el-Khalili is for many the most entertaining part of Cairo. It is an ancient shopping area, nothing less, but some of the shops have also their own little factories or workshops.
The suq (which is the Arabic name for bazaar, or market) dates back to 1382, when Emir Djaharks el-Khalili built a big caravanserai (or khan) right here. A caravanserai was a sort of hotel for traders, and usually the focal point for economic activity for any surrounding area. This caravanserai is still there, you just ask for the narrow street of Sikka Khan el-Khalili and Badestan.
Khan Khalili Bazaar, it stays open till late, and is a very interesting area for monuments as well as shopping.