Last night I was watching Robot Chicken, and they had a segment about "Zombie Idol" where dead zombified rock stars were competing. John was one of them, being helped along by Yoko. They were only on screen for about a second, just long enough to recognize.
There's also a Yellow Submarine parody on Robot Chicken.
Also, on Cracked.com, someone uploaded a video of the Worst Saturday Night Live Episode Ever (which consisted entirely of "And tonight featuring...." moments), and Ringo was one of the celebrity guests.
BTW, that Munsters episode? I remember very clearly that the Beatles were NOT given proper attribution for the song in the end credits. I was very offended!