I stumbled across this video and thought it has some great ideas for dogs post surgery (many owners struggle to keep their dogs entertained after patella surgery for example!), on crate rest for bad backs or other reasons, dogs that have reduced mobility, or have SM and need to do gentle activities -- or just on a rainy day:
https://www.youtube.com/watch?v=YfL99xcEpXc
https://www.youtube.com/watch?v=YfL99xcEpXc