I would recommend a visit around the city. In the day, you could get in a visit to many sights and Giza Pyramids.
But I would also recommend getting informed with someone in or around the community to make sure you do not get caught up in any protests.
Alternately, a concierge at a Heliopolis hotel may be able to organize a day tour for you. If you book with a reputable chain, you should have a guide that speaks English and keeps you out of any harms way:
17 hours is plenty of time. If you've never been to the city before as was suggested you should visit the pyramids. You'll probably have time to squeeze in the egyptian museum in tahrir square or the citadel. But you'd have to check beforehand if there're any planned strikes in tahrir square which has been considered the heart of the revolution. Have a good safe trip!
Dear worldtraveller73, many thanks for your very interesting report, which convinced me to get out of the airport and see the city instead of hanging out in transit.
It's my pleasure. It's a fabulous place and I think if you keep your wits about you and your head up, it can also be a perfectly safe place to visit. I just wouldn't go without educating yourself and familiarizing yourself with the local conditions.
I was in Cairo this past June and loved it! Booked several tours with www.memphistours.com
Very professional company, driver and tour guide. E-mail them with your requests and they will respond very quickly.
I wouldn't recommend going out on your own though... Cairo is the craziest city I have ever been to and it is not easy to navigate on your own.
If you are flying with Egyptair and have more than 8 hours between your flights, they will arrive a hotel outside the airport (most likely the Baron hotel in Heliopolis which is full of transit passengers at any time) and also the visa for you. Upon arrival you can go to a special desk and they will collect your passport and boarding pass. After about 1 hours you will be transferred to the hotel, meals are included. You can then do whatever you want - I wouldn't go to the overpriced Pyramid tours, but rather to see downtown Cairo. You can also go by subway to Tahrir square and get a glimpse of the post Arab Spring revolution atmosphere. It's quite safe to walk around. When you return to the airport you collect your passport and boarding pass and go through immigration without getting a stamp in your passport. This information is not on the Egyptair website.