An important point to get across in economics is three-fold: 1) monopolists are everywhere, 2) most of them aren’t profitable, and so 3) they don’t stay open.
The example I often give in class is that I am a monopoly provider of my own hip-hop music (videos and clothing too … and maybe I’ll expand into bling).
This is important because it means that the more-or-less standard response of most people that monopolies need to be regulated because they’re profitability is a problem is … nonsense.
Tim Worstall is a virtual friend of mine, and he’s interviewed here by NPR because he was an honest-to-god monopolist for several years.*