Today marks the last day the Royal Canadian Mint will distribute the penny, a coin that has been in production in Canada for more than 150 years.  The sinking of the Canadian penny is a recognition of the reality that it  costs  of 1.6 cents to manufacture a penny, and that many people consider them more of a nuisance than a denomination of money.   Jeff Gore  is the founder of Citizens to Retire the U.S. Penny. He's also a professor of physics at the Massachusetts Institute of Technology.