Must do's:
1- Table mountain - you should do this on the first clear and non windy day as it can get very windy here. Allow a few hours for walking and enjoying the incredible view. There is a basic restuarant and bar up there but you can also take a picnic. Nice to also time it for sunset.
2- Do a day trip (need to set out pretty early though as lots to pack in - although you could send a night in one of the towns if you wanted) to Kalk Bay (have fish and chips for lunch), Muizenberg (browse the antique shops) and then to Boulder's beach where there is a penguin colony - they walk right up past you on the beach it is so beautiful and the kids will LOVE it. After that drive on to Simon's Town which is a quaint naval town. Then on to Cape Point which is where you can see the 2 oceans meet. It is also a National Park so lots of walking and cycling routes. Apparently there is an amazing place that you can stay at there on a remote beach, I can find out the details for you if you want?
Also in that area is an ostrich farm if the kids are interested!
3- The beaches! Camp's bay is the touristy but gorgeous beach. Lots of bars and restuarants and a great vibey spot for sundowners. Local's go to Clifton 4th (next beach along from Camp's bay), another spot for sundowners: take a bottle of wine.
Llundudno beach is the best beach to go to watch the sun go down. Also no shops or anything so take your own snacks and drinks. Water is freezing tho sadly.
4- Franschoek. It is a wine area about 45 mins drive from CT. Very French as you can tell by the name, and also the gourmet capital of SA,many goregous places to eat as well as wine farms. Go for wine tastings which is lots of fun.
5- Fairview winefarm (on the way to Franschoek) has wine and cheese tasting and is lovely.
6 - The biscuit mill - a food and clothing market on Saturday mornings. Kids clothes, young designers and awesome food!
7 - V&A Waterfront - a big shopping mall as well as restuarants. Boat rides, etc etc. There is an aquarium there too which is fun for the kids.
8 - if you want to go somewhere for a leisurely lunch whilst the kids blow off steam try Deer Park Cafe in the city bowl. Large enclosed outdoor playground and great cafe
9- Die Strandloper - open air sea food restaurant on the beach - about an hour up the West Coast from CT, in Langebaan
10 - Bloubergstrand - large white beach with the post card view of the mountain. There is an Italian restaurant called Primi Piatti which also has a great sunset view, but cater for kids, with a kids area where they can make their own pizza shapes.
let me know if you need anything else!