Just fall down on some concrete onto the side of your head, get knocked out (a concussion), bruise your temporal lobe on either side, so that the neurons swell and stop conducting their electronic impules (real electricity, ie circuits), then try to remember something... bingo your recent past is all forgotten.
Depending on your age, you should be OK within 6-12 months. However, if you are a professional football quarterback...you might not even know that you have lost a few neurons in that lobe. Your agent certainly will not tell you come contract time. So, who's to know. Repeated concussions will leave you permanently brain damaged. But, you may be happier that way.
Deskstar