Introduction
I was interested in a genealogy of music genres using Wikipedia as a reference. I had some success, no doubt more to learn.
wptools
My first look at the data on wikipedia website was with wptools. wptools allows you to download wikipedia html and scrape data from them, for example content from info boxes.
I could have parsed that data into a linked list and then used that linked list to create a network map using GraphViz but before I had a chance to write that code I discovered dbpedia.