Best workout to make my boyfriend like exercising

Hello everyone :)

Long story short, my boyfriend noticed me scrolling through FB workouts and now he actually looks interested in doing them, even though the only sport he loves to do swimming/waterpolo (+occasional cycling). He's definitely not into "all this jumping stuff" :D Plus his joints are not super strong, his knee tends to hurt from intense training (long runs, jumping) and his endurance needs improvement too.

So my question is, what workout do you recommend to start with? I'm thinking about level 3 static ones, but I'd like to show him a workout that flies away quickly so that he won't get bored. (Bored easily workouts are already on my list :D)

I've been doing FB workouts for years, but I still haven't tried all of them, so I'd be really grateful if you shared with me some of your favourites or even the workouts that made you enjoy exercising. :)

Thank you all!