One way to spend New Year's Day: Sitting on Watch The Fearless Onlineyour couch in cozy pajamas, devouring a novel or ceaselessly streaming Gilmore Girls.

Another option? Plunging into frigid waters, only to step back out into the freezing January air.

Hundreds of people in the United States and Canada chose the second route on Sunday as part of their local New Year's Day traditions.

Revelers in Prince Edward Island, Canada, rolled around in chunks of ice amid fierce winds. Ontario residents stormed the chilly shores of Lake Ontario and Lake Erie. Swimmers from Washington state, Ohio, New Jersey and New York took the plunge in elaborate costumes and skimpy Speedos.

Many participants tied their hypothermia-tempting antics to a good cause.

In New York City, for example, the Coney Island Polar Bear Club raised money for Camp Sunshine, a retreat for children with life-threatening illnesses. In Calgary, Canada, the organization Old Guys in Action helped raise over $68,000 to help fight human trafficking.

Here's a look at some of Sunday's frigid festivities: