On December 12, 2010, at about 5:00 a.m., the roof had a catastrophic collapse as a result of more than seventeen inches of snow the previous day, sustaining three tears in the process. The Vikings and the New York Giants had been scheduled to play a football game that afternoon.
The game had already been postponed to Monday night due to the closure of Minneapolis-Saint Paul International Airport, and concerns of stadium officials. Because of the tears in the roof, the NFL relocated the game to Ford Field in Detroit; ticket-holders who could journey to Detroit were promised seats on the fifty yard line, while free general admission tickets for the game would be given away at Ford Field on Monday morning.
[Info from Wikipedia]