I defy anybody to find a Muppet scene from when Jim Henson was alive that's not worth 5. Muppet Treasure Island and Muppets From Space weren't the best examples of Muppetry out there. However, anything that Jim Henson did himself with Muppets, pure gold.
One of my favorites from the Jim Henson Presents show(or whatever it was called, it's the one from the late 80's) was a "behind the scenes" episode, showing how they made The Muppets, and it showed the puppeteers standing underneath doing the parts with the characters looking down and realizing that they were puppets. They broke not only the fourth wall, but also the floor.