A Muppet Family Christmas, on ABC
Christmas Specials Wiki; IMDb; Muppet Wiki; TV Tropes; Wikipedia
This was a TV movie which brought together Muppets from several different series, as well as some guest stars, I believe, and um... uh, well, I don't remember it that well. Someday I should get it on DVD or something, write up a proper review.... But I do remember Doc and Sprocket from Fraggle Rock being in it.