Favourite Bad Sitcom-Within-A-Sitcom?

I haven’t checked to see if TVTropes.org has an entry for this, but a common joke on television — mostly comedies, but sometimes dramas in a lighter mood — is to do a parody of a bad sitcom, often with its own theme song. The 10-second sitcom “Makin’ It Happen!” on 30 Rock is an example of this. (A related trope is where the characters are transported — either via a dream or some wacky plot device — into a bad traditional sitcom, which was done well on Supernatural, okay on Scrubs, and badly on My Name Is Earl.) It’s an easy target, but one that’s hard to resist. So does anyone have a favourite parody of bad sitcoms, or fake sitcom theme song, done within an existing sitcom or drama?

The fake sitcom theme song that is still in my brain, 20 years after it aired, is this 30-second bit from Just the Ten of Us where Wendy, the materialistic daughter, imagines that she has a chance to star in a sitcom about a large family making ends meet (something like the show itself, in other words), and re-tools the whole thing into a show about a rich girl and her butler. I have no idea why, but I’ve been known to sing “Wendy and the Butler” at inopportune times.