Spend time outside every day, rain or shine.
Make a recess time for the kids to get out. And then have another time where you all go together, maybe, or a nature exploration. Even better, drive to a new place and go for a walk there. It will help keep everyone healthy and sane.
Also, remember to keep things fun. If you or the kids start to get grumpy or stressed, change it up. Take a break, get a snack, play a game, build a fort. Relationships first!