Unlikely as David's suggestion sounds I can vouch for the fact that giving the drive a good hard knock in all planes can recover functionality just long enough to get data off of the drive. I have recovered data from three failed drives in this way over the years.

Obviously you only want try this when you have made sure you have tried everything else and have decided you can't afford to pay for proper data recovery. Make sure you bin the drive afterwards, so you don't risk forgetting about it and end up reusing it later...