Once again wikipedia quoted Kermit the frog as the "main protagonist" of Sesame Street, I wonder if he'll have a fight with Big Bird to really duke things out over who is really the main protagonist. One thing for sure is that he's part of a huge franchise. Here are some interesting things that I found out about Kermit.
One of the reasons that Kermit was the "main protagonist" was because Jim Henson found that he could go for long stretches operating the lighter weight of the frog.
Supposedly Kermit was made out of a green coat that Henson's mom had thrown away and his eyes were made out of ping pong balls.
Kermit is owned by "The Muppets Studio" instead of the Sesame Workshop like most of the other characters. It was only planned that he'd be on Sesame Street for one season but he's obviously been there off and on for a long time.
There is a myth that Kermit was named after Kermit Scott who was friends with Jim Henson when they were kids. The Jim Henson Company has publicly denied this.
A little bio on Kermit, he's supposedly the first frog that could talk to people and on Extreme Makeover Home Edition he said that he had 3,265 tadpole brothers and sisters.
Learning more about Kermit really showed me insight into the Sesame Street and Muppet world. I've always wanted a job on Sesame Street because it seemed like such a fun, happy place to work. You probably have scheduling and licensing conflicts even when you are using Muppets. It also goes to show that a lot of their back stories and names either come forth from myths or casual remarks made as guests on other TV shows.