This article is from the of the muppets FAQ, by Craig Silverstein with numerous contributions by others.
http://www.ncsa.uiuc.edu/VR/BS/Muppets/muppets.html http://www.muppetcentral.com/guides/episodes/tms/season1/ http://www.kermitage.com/html/epguide/tms/tmsseasons.htm http://www.best.com/~tbrowne/MuppetsTonight/
Believe it or not, the first URL holds episode guides for every "Muppet Show," "Fraggle Rock," "Dinosaurs," "Muppets Tonight!" and "Wubbulous World of Dr. Seuss" episode ever aired. In addition, there are descriptions of some of the Muppet skits from "Sesame Street."
D.W. McKim and Michael Dixon both have very substantial episode guides for The Muppet Show, at Muppet Central and kermitage respectively. The Muppet Central version is more detailed, while the Kermitage page is more complete and consciously tries to leave out "spoilers".