Also Lacey Chabert playing a parody of Jennifer Love Hewitt's character in Can't Hardly Wait. Chabert and Hewitt both starred on Party of Five.
The commentator at the football game praises Sabrina the Teenage Witch and Melissa Joan Hart in the scene after she made her cameo. Hart also was in Can't Hardly Wait.
Ron Lester, who basically plays the exact same character he was in Varsity Blues (like Gleason above). They even have a running countdown of how many concussions he has left to go before the movie ends, in reference to his Blues character's arc, which was about him being nearly killed from having too many concussions.
Molly Ringwald as the Flight Attendant. Her lines are coated in irony, at one time even saying "Fucking Teenagers" and scoffing. At one point Jake quotes Pretty in Pink to Janey, to which Janey asks "Are you sure?" and Ringwald replies "Trust me".