If someone on your gift list has expressed interest in running or walking an upcoming race (such as a 5K or 10K), consider signing him up and paying his race entry fee. Perhaps he doesn't want to do it alone or just needs a little push to register. Another idea is to pay entry fees for your whole family and to start a family tradition of completing the "Holiday Race" each year. There are a variety of races throughout the year in most areas (including kid-friendly "fun runs") and most of them benefit a charitable cause. This is a great way to do something nice for others—both the gift recipient and those benefiting from the charity!
Similar gift ideas: Entry fees for other competitive and non-competitive events (cycling, triathlon, swimming, etc.), a race day gift box for someone who regularly completes races (water bottle or camelback, energy drinks, gels, or bars), gift certificate to a running or cycling store, outdoor workout apparel for your climate.
Now you've got plenty of gift ideas for the health-conscious people in your life, as well as the loved ones who you'd like to encourage along a journey to health and fitness. Hopefully this will make your shopping a little easier this year. Happy Holidays!