When reading an article on Wikipedia, you click a link within the article and jump to a related article. On said related article, you click yet another link to a different article.
Often the article you end up with is not at all related to the original--like playing the game Telephone. This continues until half of your night is wasted.
To spend time wiki jumping:
1: Read article about Anime. Article links to Otaku.
2: Read article about Otaku. Article links to Serial Killers.
3: Read article about Serial Killers. Article links to the UniBomber.
4. Read article about UniBomber. Article links to Iowa.
5. Read article about Iowa. Article links to Corn.
6. Rinse and repeat.
Anime != Corn