http://www.imdb.com/title/tt0085017/
Even though i can't really remember any of the episodes, i do remember that i absolutely loved this show. Both the Muppet version and the cartoon version.
My friend ended up finding two of the tapes a couple years ago, and now it has just come out on DVD.
This was just an absolutely brilliant show and it was always funny to hear Uncle Traveling Matt's letters about his explorations of Outer Space (the human world) and his take on the things he saw.
With all these TV shows hitting DVD, one could go broke trying to catch back up with their favorite shows.