Lou Goldstein run a game and thought, "You know, that's really hard." This session is from Battle of the Network Stars.
Here's something else that's really hard: How do you train a dog to do absolutely nothing? You may think you've mastered it, but it's harder than it sounds. You'll remember Bob Williams and his dog Louie as soon as you hear the phrase, "He's...thinking about it." (Starts about a minute in.)
Both clips found at Mark Evanier's News From Me. If you saw something on TV decades ago and remember it fondly, chances are Mark has talked about it.