Get a head start on your holiday shopping at the annual Midtown Houston Mistletoe Market, a boutique-style market at Midtown Park. Take in the beautiful holiday decor while walking through aisles that feature fine arts, handmade crafts, epicurean style foods, holiday movie screenings, DIY Gift stations, and live entertainment. This year, for National Letter Writing Day on Saturday, December 7, you can bring the kiddos to write their very own letters to Santa and drop them in the market's "Big…