These are my own words and the sources of this information are: http://rijasy0.tripod.com/id1.html, http://www.gumbyworld.com/memorylane/histpok.htm and: http://www.pwc.k12.nf.ca/projects/claymation/historyofclaymation.html
Most people can remember the first claymation film they saw. However, most living people hadn't even been alive when claymation was invented, let alone remember the first claymation film.
Claymation dates back to 1897, when the messy art of plasticine was invented. It might not have been practical, but it was claymation. Claymation was unpopular for its first 50 years. Things got easier when Art Clokey started producing ads with characters made out of clay. Later in his life, he invented the famous Gumby and Pokey television show. They met in the third episode when, at a train station, Pokey's hoof got caught in the switch mechanism. Gumby pulled the handle and Pokey was free just as the train was about to go through.
In 1989, Nick Park invented Wallace and Gromit. These are the most modern examples of claymation and what most children have in the claymation movie bin. My favorite scene is in the short film The Wrong Trousers, it is the train scene.
In the 1980s the Pygos group created Pingu, the friendly penguin. Pingu is a show for toddlers with short claymation films, each having an educational moral. Pingu meets friends and plays with them to give preschoolers an idea of how to react in every situation they show. Credit to the Pygos group for inventing the language, "penguin".
Claymation falls into the category of stop-motion animation. This requires a slight difference in each frame, and it combines to make smooth movements and actions. If you have the right PC hardware, then you can make your own claymation film.