Date When Celebrated : Always December 12

Today is  National Ding-a-Ling Day, a very special day to ""Ring your Bell"".  Nope, we're not talking about the Salvation Army Bell Ringers, standing with their bells and kettles, outside of every store in the country. On National Ding-a-Ling Day, you should brace yourself for bizarre and crazy behavior, from all of the people you encounter today. Even normally conservative people have been known to go a little crazy on this day. 

Some people say this is a day for wackos, lunatics, and others who are off their rocker. We say, it is simply a day to cut loose, act a little weird.

What do you do to celebrate this day? Be ever vigilant to the ding-a-lings that will come out of the woodwork. Ding-a-Lings will be everywhere: on the road, on the street, in stores, and even in your house! We suggest you get into the holiday spirit, and become a ding-a-ling yourself......But, please do so for just one day.  

For the record: Ding-a-Lings and Ding Bats are not quite the same thing.

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All details taken directly from provider content at http://holidayinsights.com/moreholidays/December/dingalingday.htm