Random page is a feature present in many a WikiEngine. The point is simple: you follow a link (usually named “Random page” or something like that), and the engine redirects you to a random page.
Such links play a major role in discoverability. Take WikiPedia, for example. It has several millions of pages; just by clicking the link several times you are quite likely to come across something interesting.
Alex Schroeder: I don’t remember when I last clicked on a random page link. I’m suspecting that random pages are attractive when you feel overwhelming curiosity. I felt this way when I discovered wikis. As soon as you’re more goal driven, it loses its charm.
LionKimbro: Agreed. Unnecessary feature.
TimurIsmagilov: Disagreed. I often use this feature even on CyberRachel, the wiki which I maintain single-handedly. I often find myself visiting CommunityWiki and thinking “Hmm, I want to edit something. But what? No idea, there’s no random page”. Random pages are really good for discoverability.