In 1996, a number of Australian indie bands recorded covers of TV show themes for a tribute compilation named Box; this was released on cassette; I recall seeing a copy in PolyEster records back when Paul Elliott ran it. Now, it's
available in MP3 form. Hear
Wank Engine's cover of the Mr. Squiggle theme,
Ninetynine's version of Blake's Seven,
New Waver's characteristically Darwinian take on the Four Corners theme and some outfit named
Pigshit doing the Degrassi Junior High theme, among others. (Thanks to Greg Wadley for the heads-up.)
Smudge did a cover of the Degrassi High theme in about 1991 or 1992. They also did a cover of the Zit Remedy song. I think they only did them live, but there might be some Smudge archaeologist who knows if they were recorded.