Heidi Bowl
From Conservapedia
The Heidi Bowl refers to an infamous NFL football game which was televised on NBC, November 17, 1968, between the New York Jets and the Oakland Raiders. A close game towards the end, the Jets had kicked a field goal to take the lead 32-29 with 65 seconds left to play before it was abruptly cut off at 7:00 pm EST so NBC could broadcast a regularly-scheduled television film adaption of the classic children's tale Heidi. The result was thousands of angry callers flooding NBC's switchboard to the point of breakdown; by the time executives realized their mistake and resumed broadcasting the game, the Raiders had scored two touchdowns within nine seconds to take a 43-32 lead, and ultimately the win.
Embarassed, NBC and NFL executives made a rule dictating that no televised games would be interrupted by regular programming until after the completion of the game.