Wikipedia Roll, a Flash-based Wikipedia browsing application attempts to help provide better exploration of Wikipedia entries by doing some content/link analysis and clustering topics and sub-topics related to the retrieved entry.
The screen above shows the entry for "interaction design." You can see that the links occurring in the article, and presumably, other related topics are grouped into clusters that can be further explored. Each cluster provides a wheel tool for spinning through the group's available terms. Scrolling to the left/right on the page shows more clusters for the group.
http://api-exploration.net/mashups/wikipedia-roll/index_en.php#/Interaction%20desig