Known in Egyptian as Medinat Nasr, Nasr City is a satellite town that grew up in the east of Cairo during the 60's and 70's. Situated south of Heliopolis, it's really rather difficult to tell where Nasr City ends, and Heliopolis begins.
Nasr City is a rich area of Cairo, famous for its shopping and entertainment. There are a number of shopping malls here, such as the Genena Mall (which has a small ice skating rink!). More importantly, the City Stars mega mall is in Nasr City.
There are also lots of coffee shops and fast food restaurants, and a number of cinemas. Beyond that, there isn't a great deal to Nasr City that will interest foreign visitors to Cairo, though it does also contain the Cairo Stadium, Sadat's tomb, and the October War Panorama.