(So this isn't exactly holiday related, but it certainly will be a useful habit to get into before the holiday foods come out in force! )
Depending on your circumstances and proximity, exercising can be a great way to spend time together. If there is a trail nearby you can go jogging together, or if the weather is incliment you can do indoor exercises at home or elsewhere. If exercising together isn't practical but you still like the idea, you could be exercise "accountability partners." Even though I know I need to exercise and want to, sometimes it take little push to actually get me moving!!