Maadi is an expat and embassy enclave about 12 km south of Downtown, on the east bank of the Nile. It's an extremely affluent area, populated by rich Egyptians and expats, and particularly popular with Americans, and families working in the petroleum industry.
Most of Maadi is much greener and quieter than the rest of Cairo. The streets, planned during the early 20th Century by a retired Canadian military officer, are mainly laid out in a grid-iron style, and are known by number rather than by name.
Whilst it's undeniably one of the best places in Cairo to raise a family, Maadi feels rather soulless compared to the rest of Cairo. There aren't really any sights here to attract visitors, though Maadi is home to some of Cairo's best restaurants, as well as a handful of decent bars. Most of the action takes place along Road 9, which is a strip of restaurants, cafes and shops.
Maadi is also one of the best places in Cairo to do a felucca ride, since there are no bridges to get in the way. You can enjoy a relaxing, uninterrupted sail on a nice, green part of the river.
Finally, if you are desperate to visit a large mall, Maadi proudly hosts a Carrefour, which is actually quite a good place to buy electronic equipment.
Maadi also has three metro stations (all on Road 9) and so is quite an easy area of Cairo to get to.