Hey man,
I run a small sketch group that usually meets once or twice a month. Our usual haunt is Truth HQ in Town, and I sometimes host sketch meets at Utoo Cafe in Claremont. Just do a search for "OpenArt Cape Town" and hit the like button on the page to get updates (I would link you to it but FB is blocked at work). People who pitch up are sometimes inclined to draw people around them, sometimes they bring their own work, and sometimes they just sit around, drink coffee, and chat. I have no issue with the just chatting part as long as you're not bothering someone who isn't in a chatty mood.
Friends of mine are also part of the Legion Ink group and run monthly meet ups. These meetups are less frequent so they tend to be bigger. We're going to be at the Seapoint park this weekend I think. The details are probably on the Legion Ink forum.