Keep your core temperature down with dinner and a movie – and dessert – at Post 390. Skip the popcorn and the candy on your next theatrical outing and head for the Back Bay, where your ticket stub will get you an after dinner treat: a waffle sundae with popcorn ice cream, root beer caramel, caramel corn and chocolate sauce; or, for traditionalists, a classic  vanilla ice cream sundae topped with Taza hot fudge and whipped cream. The deal includes one sundae per entrée (yes, you have to have dinner first but they don’t really care if you eat all your vegetables). Call Post 390 at 617.399.0015 for details (and check here or here for nearby showtimes).