Gebel Asfar used to be all the rage about 10 years ago. it is basically the main sewage area for Cairo so you can imagine what it is like! Actually, having said that, you soon get used to the smell and there were lots of orange groves to walk around, as well as various pools and pits!
I don't know what access is like these days, I don't see it in any of the trip lists any more. We went there three days in a row, and only had trouble accessing it once - when someone had put the barrier down, preventing us driving up the road.
All the normal birds you would expect to see are there, Cattle Egrets, Wood Sands, Red-throated Pipits, Zitting Cisticolas, Clamorous Reed Warbler, Senegal Thick-knee Purple Swamp-hen, Little Crake etc. more interesting birds include Senegal Coucal, White-breasted Kingfisher and Painted Snipe.
I don't remember too many birds in Cairo itself - Senegal Thick-knee outside the airport, Spanish Sparrow, Yellow-vented Bulbul, Laughing Dove, Hoopoe and Black Kite being about the best things we saw.
If you have a couple of days to spare, I advise getting a taxi (very cheap) to Suez for the raptor migration (House Crow for your Western P list too!)
Darrell