Easter egg: On the series 1 DVD, allow the main menu to come up on screen. Wait for the menu 'loop' to come to an end. When the menu starts up again, a phone will ring. Press select to get a full length version of 'Free Love Freeway' which was shot for the episode 'Training.'
Easter egg: On the third disc of season 6, select "bonus features." Once the bonus features menu appears, press up and the cherries next to the "next" button should have a red circle around them. Press enter to see Bill Lawrence and Randall Winston discuss season 7 plot points.