A business associate from America is going to be on a 24 hour sleep over in Gauteng. He asked me to show him around. So what do you show somebody like that in one afternoon? I will be working in the morning so I only have the afternoon. Preferably close to the airport. The Apartheid thing at Gold Reef is to depressing. The Loin Park is a bit artificial. I also need to take him out for supper. A nice place to eat close to Emperor Palace?
Perhaps a very quick visit to the Cradle of Humankind?
When I lived in Alberton for all of three months, the coolest thing I could find in Johannesburg was the zoo. But if that’s a bit naive for your taste, why don’t you guys go catch a few beers, doesn’t really matter where, and show him some pictures of Port Elizabeth? 8)>:D 
Rigil
I hear the SAB beer tour is nice. I do not like their beer but I might do that. As for PE this pic is worth a thousand words (or something like that) 
Or you could be really original and try out a Nigerian drug and prostitution nest in Hillbrow… >:D
Take him to a shebeen, I’ll ask around for a descent one near the airport, they have evolved into proper tourist destinations with all the right touches of Africa thrown in and he can eat some “pap and stew” with his fingers whilst watching a traditional African dance.
You see in CT you can go up the mountain in an afternoon. In JHb, if you can get into the gold tour at Gold Reef is probably the best way to tell the story of Joburg. Else the east rand is kak depressing.