Fun with Kazaa: do a
Fun with Kazaa: do a search for audio, with title words containing the word "cover." Download anything that looks remotely interesting, a good rule of thumb is to maximize the juxtaposition (punk bands doing 80's covers, classical version of heavy metal classics, country bands covering gangsta rap).
After finding quite a bit worthy enjoying, I was struck by something claiming to be Greenday doing Wonderwall. It sounded more like two teen non-native speakers of english with an acoustic guitar, singing off key and out of time. Here's the track and here's the Bitzi record for that song.
There's something infinitely more interesting about imperfect renditions of songs you're familiar with. I'm reminded of Brian Eno's Portsmouth Sinfonia project, a symphony comprised of people with little-to-no musical training, playing the classics. There's something great about this wonderwall cover that I can't put my finger on, but I'd rather hear this version over the Oasis one.