The SP Timeline
Gleaned from: other sites, the South Park Digest, various interviews the duo have done for TV and print (31 and counting), newsgroup posts going back to 1997, David Goodman's articles in Salon Magazine, and newspaper articles.
NOTE: All links will stay up for the current year. At year's end, any expired links will be removed. If alternate links are available, send them in. If there's an item that you think belongs in the timeline, send that, too. :)