(Sioux Falls, SD) — People are preparing to brave freezing cold water for a good cause. The 36th annual Polar Plunge begins on Thursday in Sioux Falls. Proceeds this year will benefit the Special Olympics of South Dakota. Registration starts at 5 p.m. at the Unify Center. For those who don’t want to take the plunge, you can still raise money that will benefit Special Olympics athletes with the chance to play sports and compete with no costs.