I don't care for songs that get their humour out of looking at the surface of a genre (eg. C&W), then putting it down. Most of the so called C&W parodies I find quite boring, and they indicate a superficial understanding of country and western music.

That being said, one song I think might fit the "so bad it's brilliant" category is Mickey Newbury's "Just Dropped in To See What Condition My Condition Was In". Kenny Rogers & The First Edition's version of it was OK, but Mickey Newbury's is brilliant He even has a Vanilla Fudge dirge like "Mary Had a Little Lamb" line thrown in.

The song is very funny--yet such an incredibly accurate depiction of the "psychedelic experience" depicted in many songs of the late 60's.