Cape Town is a beautiful city. As for things to do? These are some things that I enjoyed when I visited:
1. Visit to Table Mountain (a must)
2. Kirstenbosch Botanical Gardens
3. Visit to Victoria & Albert Waterfront from where you can get a ferry to...
4. Robben Island (a must)
5. Book a full day tour through wine country, Cape of Good Hope, Penguin Colony etc.
6. Visit the District 6 museum
7. Walk around Bo Kaap (Malay/Muslim Quarter). Very pretty, colorful houses
8. Just walking around the city with no agenda is also great fun and a good way to "discover" interesting things.
9. Etc. etc.
I used this tour company to make my bookings http://www.daytours.co.za/
for any tours. They are very professional, courteous and punctual!
If you enjoy reading, a good starting point is to read The Covenant by James Michener. It's a fantastic historical novel (very thick), and it will give you great insight into South Africa.
Have a great time. Cape Town is one of my favorite cities.
[Edited 2007-02-02 12:47:59]
The only thing we have to fear is the sky falling on our heads. -Asterix