What is boring to do, but fun to watch?
Poker on TV is exciting. Live, it can be a drag, especially if you're "card dead".
Depending on how much the average person enjoys it, perhaps being involved in making movies/TV shows.
Recently for me, it is Video games. For some reason, I start playing full of motivation, and then after 15 minutes im sitting there like "hm, this is exhausting, and not really that fun anymore...". I do love watching Twitch Streams of those same games though!