Hidden Audio clips
Go to the "Options" menu, highlight the "Resume Episode", then press Left to have lightning highlight the reactor. Press Enter to hear the cast say lines from their next Star Wars spoof.
Hidden trailer
Go to the "Features" menu, highlight the "Family Guy Promo" option, then press Left to highlight the bubbles. Press Enter to see the teaser trailer for the next Family Guy Star Wars spoof episode titled "Something, Something, Something, Dark Side."