I listen to some music some folks might consider "Mediocre" but in terms of appallingly bad, you cannot go past "The Hollar Dores"
They write songs about screwing underage chicks, and they have a romantic duet which has the catch line "Your love is sweet and moist and tender, like a vagina, trapped in a blender"
I like to think of them as Anal Cunt, except a bit more subtle, and if AC got bored and tried to play Pop Punk instead.
I think they broke up a while ago, and I have only seen them a few times, but I will never forget my 18th birthday, when some friends and I hit the main indie music place in my city and saw these guys belting out their stuff, like crazed madmen. Truely a great moment in my life.