Depends on the weather... if it's nice outside, I'd be working in my garden, go running/biking. I'd catch up with my girlfriends. I'd read a book. I'd take a long bath. I'd work on one of my many hobbies. I'd take a road trip, go to a museum...
and, I would miss my kids. But I would enjoy the fact that they were off having a fun time hanging out with their father.