This was, quite literally, the first thing from MST3K I ever saw. I was randomly flipping the channels and happened across this very bit. I almost flipped past it until I recognized Joel Hodgson and wondered what in Hell he was doing with a bunch of puppets on late-night TV.
I went from not knowing about the show's existence to being absolutely in love with it all in the space of five seconds and that was even before I knew they spoofed all those great cheesy old movies I loved as a kid.