Dine in costume at la Spiga, on a five-course mystery menu with wine-pairings and Halloween-inspired cocktails. The best costume of the night will win a gift certificate for dinner for six. Time: 5 p.m.-midnight Sat., Oct. 31. Location: Osteria la Spiga, 1429 12th Ave., 323-8881. RSVP at 323-8881 or hello@laspiga.com.Price: $35 dinner, $60 with wine pairing. A portion of the proceeds from the evening will go to the Susan G. Komen Fund. The Hideout throws its 4th Annual Costume Party, offering the perfect low-light venue to try out your goriest, sexiest, or cleverest costume. The stylish bar promises good music and well-crafted drinks, as well as candy and a colorful crowd. Time: 6 p.m.-2 a.m. Sat., Oct. 31. Location: The Hideout, 1005 Boren Ave., 903-8480.Price: Admission is free, drinks are not.