If you're looking for something unique to do to mark the winter solstice, consider checking out the sculpture Gestation III in Palisades Park. The piece of public art sits on the cliff walk all year round, waiting for the moment when the sunset lines up perfectly to display in the center of the sculpture. Each a year a small group of locals gathers—mostly with camera in hand—to observe the sunset on the shortest day of the year.
Because the exact moment of the equinox can fall on either December 21 or 22, the phenomenon is generally viewable on either night, weather permitting.
Note that the annual sight is only visible for a few minutes, and people wait all year to see this. If you bring small children, please don't let them climb on the structure while the sun is setting.