Gaza is not exactly a top tourist destination and most of its attractions have taken quite a beating during the past 50 years. The following are all in Gaza City.
The Great Mosque Jamaa al-Akbar makes up for its lacklustre appearance with an interesting history: it's a converted Crusader church built on the site of a Hellenic temple with pillars from a 3rd-century Jewish synagogue.
More educational might be a UNRWA-arranged visit to one of the refugee camps that dot the strip. The UNRWA office is on al-Azhar St, near the Islamic University, call ahead to see if they can arrange a little tour. Your most probable destination is the optimistically named Beach Camp, a warren of concrete huts and open sewers housing 63,000 people, built next to a sandy beach - and you can walk there on your own, 15 minutes to the north from the intersection of Omar al-Mukhtar St. with the seafront road. UNRWA wisely recommends avoiding military clothing. The Jabaliya refugee camp is also a nearby option.
Hamam al-Sumara. The last of the 'turkish baths' in Gaza. Different hours for men and women, excellent service and a proper scrub down. Between Palestine Square and the Saladin Road.
