Die-hard Nirvana fans might want to cover their eyes and ears for this one. In the age of the mash-up, it was really only a matter of time until they began the desecration of music idols - but I bet no one expected to ever see the words "Nirvana" and "Rick Astley" in the same sentence, let alone singing side by side. Surprisingly enough, it kind of works - in a weird, twisted way.