In my wanderings I found this neat little example using dinner parties to explain two sided markets (source):
The task facing a certain kind of entrepreneur these days is no more unfamiliar than the engineering of a successful dinner party. The French ambassador would never so much as respond to an invitation — unless you intimated that Rupert Murdoch, say, would be there, in which case he would accept. Murdoch, if he thought that the Attorney General would attend, would show up, too. And if you led the AG to think his dinner partner would be his favorite movie star, who, you let slip, so badly wanted to meet him (while telling her the same thing) …. Well, pretty soon you’d have a famous dinner party. After three or four such successes, your reputation as a host would make your job much easier, with chefs, provisioners, decorators, and florists anxious to work for you.
Interesting analogy, I imagine anyone who has ever oranised a party will sympathise with this description:)