If just the thought of swimming in the Bay induces hyperthermia anxieties, you’ll probably chose to be a spectator at the wildly costumed 5k and 10K race plus polar plunge at Aquatic Park this Saturday from 10:30 to 1:30. You can watch for free or participate for a $125 donation which gets you an event t-shirt and goes to support a year’s activities for local athletes with intellectual disabilities.