Do you remember, in the 1970's and into the 1980's, those very cheap Top of the Pops LPs, usually sold in Woolworths? For about 99p you could buy a compilation album of current (or very recent) chart hits... that were sung and played by session artists, not the original band.
I had 3 or 4 of them, and played them a lot - what's curious now is sometimes if I hear the original recording of a song, I don't like it - I preferred the version I was used to on the Top of the Pops LP!
I heard a programme on the radio a few years ago about the LPs. The singers and musicians had very little time to learn or rehearse the music, sometimes just a few hours of listening to the original record then having to sing and play their version of it. They didn't have original lyrics, so when they weren't sure what the proper words were, they'd improvise!
That sounds a recipe for disaster, and some of them were pretty poor, but others were astonishingly well done.
Try these for surprisingly good, hastily recorded cover versions :
Autobahn (Kraftwerk) :
http://youtu.be/Ww7w0p99ibALife on Mars (Bowie) :
http://youtu.be/n3on2vVAK_oBohemian Rhapsody (Queen) :
http://youtu.be/3HetQa0eyYkand, for balance, here's how awful they could sometimes be
Joan of Arc (OMD) :
http://youtu.be/a2CgDMVV-rsThey're worth listening to all the way through, but you're allowed to stop the last one before it finishes.
Ian