Although it's definitely going to be cold outside, the second portion of Longest Night consists of stepping outside to gaze at the stars.
A telescope or other viewing device isn't necessary; instead, try to pick out constellations and shapes based on what the unassisted eye can see. This will help everyone be able to see the constellations rather than just whoever is using the telescope.
It may not seem like it, but stargazing is the perfect activity for Longest Night in that it invites us to marvel at the wonders of the universe. It can also be very empowering; as astrophysicist Neil deGrasse Tyson writes: