ABC, CBS and NBC offer network news programs each evening, generally airing at 6:30 or 7:00 p.m. in the Eastern Time Zone (5:30 or 6:00 p.m. in other areas), however these are sometimes subject to pre-emption on weekends and select holidays due to sports programming that overlaps into the time slot, either because the event is scheduled to occur later in the day or extends beyond the set time block (due to regulations imposed by sports leagues, particularly as a result of the infamous 1968 "Heidi Bowl" telecast in which NBC interrupted a National Football League (NFL) game between the New York Jets and the Oakland Raiders to air a made-for-television film in its scheduled time slot due to a failure in communications between network executives, most televised sporting events are required to be broadcast until their completion).