From Disc One's "Special Features" menu, click on "Commentaries". Now, highlight "Main Menu" and press right to highlight the lawnmower. Hit enter to view the vintage 1950's short film "A Mowing Lesson for Charlie".
From Disc Three's main menu, highlight "Special Features" and press left to highlight the town map. Hit enter to see a special "thank you" message from Hank Hill saluting all the folks who worked hard on the first season of the show.
Reviews: DVD Talk also has a review of
King of the Hill: The Complete First Season by Jason Bovberg.