Here are a couple of games based on Wikipedia:
1. Joining Back [The name I give this game]
To begin, a random page on the Wikipedia database is loaded (Random page link in the left navigation menu). The player is then given twenty seconds to orient him/herself to the subject matter on that first website (called the 'Homing Page'). Once this 'Reading Period' is up, the player is then transported to completely different topic page after a series of hypertextual selections ('clicks'). More specifically, this displacement is caused by first selecting a random link on the Homing Page and then on ten subsequent pages.
After arriving at the final page in the randomized succession, the player must reorient him/herself and begin playing the actual game. It is the object of the game to find one's way back to the Homing Page using as few clicks as possible. The player can use any wiki-link inside the contents of any entry page they come across. These links can appear as either images or words."
Game invented by Sumana Harihareswara and implemented by Kevan, December 2006.
Get the list of all the categories that an article belongs to (at the end of the article), your opponent must guess which article it's describing.
3. Get there first [The name I give this game]
grab a laptop and challenge someone else on a different laptop. Both people go to Wikipedia and start in the same spot. [...] Then someone calls out a word or term or person, like "Bob Dylan," and they race to see who can get there first. The rule is you can't type anything; you can only click on links. And you can't go backwards.
A different version of this game is always to start from the homepage.
Wikipedia itself has a description of a version of this game too.
First, find a useful Wikipedia article that normal people might read. For example, the article called "Knight." Then, find a somehow similar article that is longer, but at the same time, useless to a very large fraction of the population. In this case, we'll go with "Jedi Knight." Open both of the links and compare the lengths of the two articles. Compare not only that, but how well concepts are explored, and the greater professionalism with which the longer article was likely created.