Something I never got around to doing is going down a gold mine or visiting a refinery, although I have had opportunities.
I have heard from more than one source, though, that some South African guides, when showing visitors gold bars, would tell them that if they could pick one up with one hand, they could keep it. After everyone who wanted to tried and failed, the guide would then pick it up with one hand. Apparently a rapid turn of the palm does the trick, although I haven't seen it done. (I imagine that a sprained wrist could also result.)
If you did manage to pick up a bar, though, I'll bet that they still wouldn't let you walk out with it.
VIP guests were sometimes given ice cream desserts sprinkled with gold dust and told that gold has many uses and you can even eat it.