If you feel like getting away and seeing something completely different, go to the gold mines in Geita. Geita is a beautiful area and very different from Mwanza. You can arrange for the trip to the mines through Serengeti Services (ask for Vinay) or by arranging it with some of the miners from South Africa or Australia. You will always find them hanging out at Tilapia - they are very friendly and easy to get in contact with, and I'm sure they would be happy to assist you in paying a visit to the mines. Geita city in it self is nothing special, and I wouldn't recommend a longer stay there. It is a typical mining city with all the prostitution, crime and drugs that follows,
Want a masaai necklace?
Mwanza has a miniature masaai market, where you can buy masaai necklaces, rings, headbands, jewellery, medicine etc. It's not much and you may be a bit disappointed about the selection, but you can get some good offers here, and face it - if you're not going to Arusha Region this is the only chance you have of bying a Masaai souvenir.
Ask the locals for directions.
Sounds like a weird idea to visit an orphanage? Well, maybe it is, but it is also an experience that gives you a very good idea of what life is like for many children in Mwanza. At Kuleanas, street children are offered education, food, a place to stay as well as medicine, and the staff tries to reintegrate some of the children back into their families. It's by no means luxurious and most of the kids run away over and over again. It's amazing how these children survive considering the hardness they experience, and going there makes an impression on you. Kuleana is of course NOT a tourist attraction, so be considerate if you are allowed to go there. Ask the manager if you can see the place and have someone show you around and talk to the children. Maybe you'll see some of them on the streets next day.