A Zamboni took a dip in North America's largest groomed skating pond at Keystone Resort tonight.

Quote from the article:

A driver was grooming the lake at about 6:15 p.m., when the ice cracked and the 7,000-pound machine began to sink at about 6:15 p.m. As a precaution, skaters were cleared from another area of the 5-acre pond, resort spokesman Ryan Whaley said. The driver was not injured. There was no word immediately on how soon the rink might re-open, but staff will examine the ice and remove the Zamboni Wednesday, Whaley said. "They'll take it out and we'll see how it is," Whaley said of the machine and the safety of the ice around the crater.

Source: Keystone Lake Zamboni falls through thin ice