Also, I remember when Jim had Dr. Teeth with him on The Tonight Show with Johnny Carson. And at MuppetFest, (even though I wasn't there...grrrrr) performers such as Jerry Nelson, Dave Goelz and Bill Barretta sat in chairs and performed favorite Muppets in front of a crowd.
I also enjoy the episode of TMS with Senor Wences with the running gag of Muppets such as Gonzo and Statler talking about how puppets are unnatural and freak them out. At one point, after Gonzo says his bit (to Kermit) and walks away, Kermit looks at the camera and says, "I didn't have the heart to tell him."
Muppets are puppets and everyone knows it. I remember watching TMS or SS as a kid and seeing a puppeteers arm behind one of the characters. I liked pointing it out to my dad but I didn't care. It didn't change the way I felt about such lovable, interesting and fun characters.