The Muppets are a group of puppet characters created by Jim Henson starting in 1954–55. Individually, a Muppet is made by Jim Henson or his company's workshop. Although the term is often used to refer to any puppet that resembles the distinctive style of The Muppet Show, the term is both an informal name and legal trademark linked to the characters created by Henson.
The word "Muppet" itself first appeared in 1956, and was said by Henson to have been created by combining the words "Marionette" and "puppet". However, Henson was also known to have stated that it was just something he liked the sound of, and he made up the "marionette/puppet" story while talking to a journalist because it sounded plausible.
After earlier unsuccessful attempts, The Walt Disney Company bought the Muppets in 2004. Exceptions include characters appearing on Sesame Street (as they were previously sold to Sesame Workshop, although they have always had creative rights, only paying The Jim Henson Company to create and provide their Muppet characters for their use) and the Fraggles of Fraggle Rock (which are still owned by The Jim Henson Company). The legal trademark on the term "Muppet" is currently held by The Muppets Holding Company (now The Muppets Studio, LLC, a division of The Walt Disney Company), although Sesame Workshop and The Jim Henson Company continue to use the term on their characters with certain permissions.
After more than 10 years, a new movie is in the works. Disney recently enlisted Jason Segel and Nicholas Stoller to create the next Muppet movie for the studio. This will be the first Muppet theatrical film since Muppets from Space. In January 2010 James Bobin signed on to direct.
The Muppets' latest television special, A Muppets Christmas: Letters to Santa, premiered on NBC on December 17, 2008. It was released on DVD on September 29, 2009. A Halloween TV special featuring the Muppets was expected to air on ABC in October 2010, but was shelved due to an upcoming film.
Source: Wikipedia, "The Muppets", available under the CC-BY-SA License.