New Year's Eve is traditionally a time of partying. It can also be a time of opportunity and, given that we are officially a white-hat playground, I'll phrase this in the way of providing security advice.
Many routers, particularly older ones, have login details clearly printed on the back of them. If you are having a house party and any of your guests have a nefarious bent they may make efforts to inconspicuously palm their mobile, gently slide it down behind your router and take photos of your logins. This is, I would imagine, a damn sight easier that using the numerous wifi hacking techniques discussed elsewhere on Null-Byte.
Stay safe folks!