For a couple of seasons, 'Idol' took a liking to the modern-day crooner (think "rocker chick," but for guys); and in season 5, that role was filled by 17-year-old David Radford.

But while he crooned his way through Hollywood Week, Radford made the show look, well, crazy in the semifinals when he butchered the Queen song 'Crazy Little Thing Called Love.' The performance was flat, awkward and, if anything, reminded us of another ill-fated crooner: season 3's John Stevens.

That alone was reason enough to put Radford on our list of the worst 'American Idol' semifinalists ever. To read more about his trajectory on the show -- and to see what he's been up to since -- visit Vote for the Worst.

Bad performances on 'American Idol' aren't just limited to the audition room.

In just seven seasons, we've seen over a handful of performances bad enough to shut down any karaoke bar in the country -- everything from Carmen Rasmusen's 'Can't Fight the Moonlight' to Jon Peter Lewis' 'A Little Less Conversation.'

The members of Votefortheworst.com (VFTW) recently narrowed down the performances and compiled a definitive list of the top 20 guiltiest 'Idol' pleasures of them all.

Click through the gallery to see their picks. Just don't forget to bring your earplugs.