Wikipedia:Get_to_Philosophy is not what xkcd is describing, though. That page seems to allow any link to be chosen. xkcd says, "click on the first link in the article text not in parentheses or italics".
For example, Wikipedia:_Get_to_Philosophy provides the example, Optimum "L" filter -> Butterworth filter. But the first link in 'Optimum "L" filter' is "Athanasios Papoulis".
Wikipedia has the answer, as to not spoil here's a link. http://en.wikipedia.org/wiki/Wikipedia:Get_to_Philosophy#Cha... I like the last loop on the article not crossed out.