The best thing to do on a rainy day is to snooze.
Yesterday I got a couple of dog blankets out and covered the girls whilst they were in their beds. I have the heating on, but both girls had been curling up and tucking their nose under them, so I thought they'd be cosier with a blanket. Well neither moved for some time, so they were a hit.
Don't forget to hug your hound/s.