Dude, yer Stocked. Cape Town is such a beautiful city. I stayed in Kalk Bay/Simon's Town and loved wandering around in the early morning, watching the fishermen ready their boats and whatnot. There's a fuggin penguin beach where you can chill and watch those little idiots bobble around on the rocks and swim through the crystal clear water.
I was there in March and I was surprised how cold the water was on the West coast. Noordhoek was the funnest wave we got but to be honest it wasn't exactly pumping. Would like to go back when there is more swell.
I think doing the hike out to Cape Point is a must if your knee is up for it. Unforgettable vibes.
When exploring around just be cognizant of the fact that there is some dangerous areas. The coast is mostly nice and built up and safe feeling but inland, where the townships are, can be pretty sketch.