Organizers with the annual University of Okoboji Winter Games Polar Plunge said this year's turnout shattered previous records, ultimately generating $5,000 for the Arnolds Park/Okoboji Fire and Rescue crew on top of another $5,000 donation from event sponsor Okoboji Motor Company. Staff with the Iowa Great Lakes Area Chamber of Commerce said more than 300 people registered to take the icy dip in West Lake Okoboji on Jan.