This Sunday, The Gillespie will host the Olmsted Parks Conservancy's annual Halloween fundraiser party. The Boo La La Halloween Ball features dinner, cocktails, dancing and a costume contest. Cocktails will be served at 6 p.m. and dinner at 7:30 p.m. The post-dinner party starts at 9 p.m., with plenty of cocktails and dancing. Come dressed in costume or black tie.