Cross Country Skiing (commonly referred to as Nordic Skiing or XC Skiing) is
the world's finest fitness activity; which works the arms and legs simultaneously.
Not to mention, that it serves as a great cardiovascular workout.
To participate in this sport, you require boots, poles, and skis. The primary
difference between Cross Country Skiing and alpine (downhill) skiing is that
in XC, your heel is not attached to the ski. The free heel allows a XC Skier
to ascend, descend and traverse terrain making the sport very much a "cross
country" activity.
So grab a pair of skis and chalk up your fun as cardiovascular workout.