Bo-Kaap. This neighbourhood, located on a hill south-west of downtown is the area historically inhabited by mainly Muslim descendants of slaves from South-East Asia (hence an older term for the area - 'Malay Quarter'. It's a common location for film shoots, as there are some very colourful buildings, quaint streets, mosques. views over Cape Town and some great food sold on the side of the street. It's well worth wandering around for an hour or so, as well as visiting the Bo-Kaap Museum (a view of a prosperous Muslim family from the 19th Century). Atlas Trading is and old fashioned shop where you can buy spices for any dish. Ask the proprieter to mix you the necessary spice for the meal you intend making. Approximately 1km from the Bo-Kaap, is the Noon Gun which is fired every day at noon - from Monday to Saturday. You can go and view the short ceremony that takes place before the actual shooting as well as the shooting itself. 
The Castle of Good Hope, Buitenkant Street, ? +27 (0)21 464-1260, . Popularly called 'The Castle' by locals, it has extensive displays of historical military paraphernalia, a history of the castle, an art collection and the William Fehr Collection (including old Cape Dutch furniture). You can eat inside the Castle at the restaurant or café, as well as buy wine. R25 entrance fee. 
Kirstenbosch Botanical Gardens, Rhodes Drive, Newlands, ? +27 (0)21 799-8899,. Open daily 8AM to 6PM (7PM September to March). View the hugely diverse and beautiful plants and flowers of the Cape flora in one of the most stunning botanical gardens in the world. Plants from all of the regions of South Africa are on display, including rare succulents from the Richtersveld, a giant baobab tree, and interesting medicinal plants. Numerous paths wander through the grounds situated on the back side of Table Mountain. Several restaurants, a gift shop and indigenous nursery are also available. At various times of the year concerts are performed in the open air amphitheatre. Art is frequently on display, including large Shona stone sculptures from Zimbabwe. The gardens are also home to the National Biodiversity Institute. What makes the garden so special, is that every season gives you something new to see - new flowers, different birds, etc R27. 
Robben Island, ? +27 (0)21 413-4200. Robben Island is located just off the coast from Cape Town, this was the location used during the apartheid days to hold political prisoners, including Nelson Mandela and the late Walter Sisulu. Some of the tour guides were themselves political prisoners so they have plenty of insight about what went on there. Tours run several times per day, seven days a week from the Nelson Mandela Gateway at the V&A Waterfront. As of December 2008, tickets can be purchased for a tour the next day, although it is advisable to make a booking as soon as you arrive in Cape Town. Tickets can be purchased online. R200. 
Rhodes Memorial, ? +27 21 689 9151 .Built in recognition of the contributions of Cecil John Rhodes to the Southern African region.
South African Parliament, [38]. Cape Town is the legislative seat of South Africa (the Presidential seat is in Pretoria and the Supreme Court is at Bloemfontein). A tour of this compound will acquaint you with South Africa's recent history and its political system. The tour includes visits to the National Assembly, the National Council of Provinces and the old apartheid-era assembly which is now only used for caucus and committee meetings. Tours are offered a few times per day in various languages. Free entrance and tours. 
Two Oceans Aquarium, V&A Waterfront, ? +27 (0)21 418-3823 . Open 9:30AM to 6PM. An excellent modern aquarium. R94 entrance fee. 
Victoria and Alfred Waterfront, ? +27 (0)21 408-7600, [40]. A huge shopping and entertainment area at the slopes of Table Mountain, next to the harbour. It is very popular with tourists, because of the high density of shops, restaurants and amusement possibilities, like the Aquarium  or the Marine Museum. Harbour tours and trips to Robben Island start from here, as well as helicopter flights to the Cape Peninsula. The V&A Waterfront has more or less full wheelchair access