EyePlorer is a reference search engine that takes your original search term then displays related terms in a circle around your original search term. Clicking on each related term reveals more information from Wikipedia about that term. If the information is something that you want to save for later use, you can drag the information into your EyePlorer notebook.
http://www.freetech4teachers.com/2010/02/eyeplorer-visually-explore-wikipedia.html