>You have a soda machine that has three buttons, Coke, Pepsi, and Random (Coke or Pepsi). You know that your trickster coworker has swapped all of the button labels, so none of them are correct. What's the optimal strategy for getting a Coke out of the machine?

I prefer Pepsi to Coke, so I wouldn't attempt to get a Coke. The optimal strategy is, of course, to get a crowbar, pry the machine open and take what you want.

That's the optimal, least expensive strategy -- assuming you have access to a crowbar.