Fri. Oct. 31

 Is there a restauraunt/club that does not love Halloween? Especially when it falls on a weekend? It's time for that lovingly ghoulish celebration of all things dead and gory, with costumes and cute names for stuff and in general, an opportunity for adults to behave like they're kids for a short spell. Upstairs on the Square is having, what we would probably call an "upscale" version of Halloween in that it's got a $35 Prix Fixe menu, a costume contest, special $9 cocktails, like the Bloody Sidecar (V.S. Cognac, Mandarine Napoleon Orange Liqueur, Citrus Juice with a Blood Orange Bitters & Sugar Rim), Dark & Stormy (Cruzan Black Strap Rum and Our Housemade Ginger Beer) and
Crime of Passion (Passion Fruit Puree, Barenjager Honey Liqueur and Champagne). The five course dinner with wine pairings - a $200 value - includes: Headless Pumpkin Patch Soup or Skewered Artichoke Hearts with Citrus & Blood Orange Lemon Sole with Forbidden Black Magic Rice or Well-Executed Hanger Steak Smashed Pepito Garlic Pesto or Frankenstein-Stitched Spinach Ravioli, Ricotta Filling & Creamy Cheese Fondue with Trick or Treat Dessert. All starts at 5 p.m. (In the photo, owners-hosts Deborah Hughes and Mary-Catherine Deibel.)

91 Winthrop St., Cambridge, 617-864-1933 www.upstairsonthesquare.com.