This is 60 anniversary of chatter teeth which is also know as Yakity-Yak chompers. Boing Boing had article on the chomper from CollectorsWeekly which gives you some of the background. Eddie Goldfarb who invented the chompers also invented Battle tops, kerplunk and Shark Attack. Here is the article enjoy.
http://www.collectorsweekly.com/articles/yakity-yak-60-years-of-teeth-that-talk-back/