On network TV, when sporting events run longer than the scheduled time, the following program (usually syndicated) is pre-empted and the game remains on air until it is finished. In other instances, network programming will be delayed until the game ends, such as how CBS always delays the start of 60 Minutes to allow it to be shown in its entirety.
This practice goes back to a 1968 American Football League game between the New York Jets and Oakland Raiders that aired on NBC, now known as the Heidi Game
(or the Heidi Bowl). It was the second game of an AFL doubleheader, which had kicked off at 1:30 P.M. Eastern time with the San Diego Chargers and Buffalo Bills in the first game. NBC had allotted a 5-and-a-half hour window for the two games (which made sense in that era, since football games rarely exceeded three hours back then), followed by the premiere of a new, very expensive and heavily-promoted Made-for-TV Movie adaptation of Heidi at 7:00 P.M. Instructions given to NBC's master control the day of the game said to start Heidi promptly at 7:00 P.M. However, by about 6:45 it was obvious that the game would run past 7:00, and in a frantic series of phone calls, NBC executives decided to air the game to its conclusion and delay the start of Heidi. But viewers had started calling NBC to ask if they were planning to stick with the game. This jammed up the network's switchboards, and NBC executives couldn't get through to master control to relay the change in plans. As a result, at 6:58 P.M., with the Jets leading 32-29 with 1:05 left in the fourth quarter, NBC cut away from the game, ran a commercial break, and started Heidi at the top of the hour. As luck would have it, in the final unaired minute of game time, the home team Raiders scored two touchdowns and won the game. Viewers on the West Coast (except the San Francisco Bay Area, which didn't see the game at all because of home market blackout restrictions) were able to see the comeback, since the Pacific Time Zone has a later, separate prime time feed, but the rest of the country was furious at NBC. Besides the network getting flooded with calls, angry viewers called local affiliates, and even newspapers and police stations (!) to complain. NBC attempted to defuse the situation by flashing a special "RAIDERS DEFEAT JETS 43-32" bulletin during the movie, but they chose to do it during an emotional scene involving Heidi's paralyzed cousin, which only served to piss off both audiences.
In the aftermath, NBC immediately adopted a policy to run live events to their conclusion, even if they spilled over into prime time. It got its first test about a month later, when a game between the Raiders (again) and the San Diego Chargers ran over by 8 minutes, and NBC delayed the start of the Hanna-Barbera series The New Adventures of Huckleberry Finn, then delayed the rest of prime time by 8 minutes (known as "sliding" in TV parlance). Later deals between various sports entities and the major networks contractually obligated networks to air sporting events to their conclusion, making it the universal policy for all networks going forward.
This left networks with two main options to handle the programs that sports overruns cut into. Either they could delay them, which would then mess up the remainder of the schedule, or begin the program at the scheduled time off the air (referred to as "deadrolling"), then join it in progress once the game broadcast finished, which would allow them to stay on schedule, but would annoy non-sports fans (and sports fans who enjoy other shows), especially since important parts of the shows get cut (on a show such as CSI or NCIS, the majority of the plot will be set up within five minutes). The join-in-progress option led to an inverted version of the Heidi controversy in November of 1975, which, coincidentally once again involved NBC and the Oakland Raiders. This time, the game ran 43 minutes over, and the network joined Willy Wonka & the Chocolate Factory (which had been heavily promoted all week, since an airing of the film had been a huge ratings hit for NBC the previous November) in progress, and NBC was once again deluged with complaint calls (though, again, the Pacific Time Zone got to see all of Wonka). The fallout from this game led networks to move away from joining shows in progress, choosing to either run their prime time schedules in their entirety (which forces local affiliates to delay their late local newscast), or completely pre-empt a show rather than join it.
Eventually networks started blocking out extra time after a game for a post-game talk show of indeterminate length. That way, if a broadcast goes long, the game will only eat into the time allotted for the post-game, which will often only last to round out the hour, and THEN go into the rest of the TV schedule. Fox became infamous for initially refusing to follow this strategy, leading to the 7 o'clock hour on Sunday nights becoming regarded as a second Death Slot due to that show's high likelihood of being preempted by coverage of NFL games. The shows Futurama, Malcolm in the Middle and King of the Hill most notoriously fell victim to this, with many episodes only being partially broadcast or burned off later in the week, leading to outrage from fans about how they were being Screwed by the Network. The outrage would increase if the preemption was caused not by the initial game but by Fox showing "bonus coverage" of a different game that was running over its scheduled time. Perhaps in response to this, Fox finally began blocking out the 7:00PM timeslot in 2006.
Because of the popularity of 60 Minutes, CBS will usually delay the start of that show until every NFL game to which it has the rights is over, then air it in its entirety, delaying the network's entire primetime schedule accordingly in the Eastern and Central Time Zones.note This infuriates fans of the network's Sunday shows (especially those that use DVRs) as they cannot predict when their favorite show will actually start (especially if CBS switches to another game for "bonus coverage", and that game goes into overtime). In September 2012, CBS decided to just bump up the Eastern and Central primetime lineups a half-hour on game nights (concurrent with the NFL moving its late-afternoon doubleheader games from 4:15 to 4:25 ET, effectively forcing the issue), though the games still leech into the second half-hour and cause delays, to the point that CBS has to maintain an Twitter/app service that sends out delay alerts; sometimes this has the side effect of killing the 10pm show for that night, a fate that befell a new CSI episode which was rescheduled three times in October and November 2014 due to long-running games.
As the quote at the beginning indicates, this is not just an American phenomenon. A variant on this significantly heightened "geek vs. jock" hostility in UK popular culture in the 1990s, due to The BBC's tendency to show imported American SF/fantasy series (such as Buffy the Vampire Slayer and various Star Trek shows) on BBC2 on weekday teatimes and cancel them altogether whenever some big sporting event happened.
On networks devoted to sports programming, there have been cases of sports preempting other sports. A notable example is ESPN's infamous 2007-14 NASCAR coverage, in which college sports was given priority, and race broadcasts were cut short or relocated; one of the most infamous examples was the 2014 Bank of America 500 (the last race aired on ABC before the new television contract with NBC went into effect the next year) had its first 25 laps preempted due to a college football game between TCU and Baylor running late; the race was supposedly relocated to ESPNEWS, where it was also preempted because of a preseason NBA game in Brazil going into overtime; the race was said to be on WatchESPN.com (which it wasn't), and RaceBuddy (a service on NASCAR's website with multiple camera angles) was not provided because the race wasn't on a cable network; the only way anyone could follow the start was through the PRN radio broadcast, or via the NASCAR mobile app. Coverage was joined at a scheduled competition caution on lap 25, at which point an apology was immediately issued by lead broadcaster Allen Bestwick and a recap of the first 25 laps shown. To add insult to injury, several ABC affiliates actually decided the race wasn't important and aired local news instead. NASCAR itself was also unhappy with the move, and apologized to irate fans.
Professional Wrestling has been a frequent victim of this, the first few years of Monday Night Raw saw annual preemptions for the Westminster Dog Show and the U.S. Open (tennis, not golf) for a week in June and two weeks around Labor Day, respectively. WCW Monday Nitro would get pushed back to 11 pm for NBA playoff gamesnote , and even to this day Fox occasionally kicks Smack Down Live over to FS1 in favor of college football or soccer. AEW Dynamite actually lost their time slot on TNT when Warner Brothers Discovery bought the rights to show NHL games, though they simply moved across the hall to TBS with the same 8 pm start time on Wednesday nights.
Although the trope is primarily associated with sporting events, there can be other causes for pre-emptions of this nature, including awards shows (which notoriously overrun) and scheduled political broadcasts such as the State of the Union address. Often networks will address overruns by either pre-empting an entire night's schedule and filling the remaining time with programming such as Barbara Walters' post-Oscars interview specials, or scheduling expendable reruns.
A mess that began with a sports pre-emption and ended with an unfortunate aversion of the concept happened on CBS on April 14, 2024. Coverage of The Masters was supposed to end at 6:57 P.M. Eastern, but instead ran about a half-hour over. Coming back from the concluding break of the coverage, rather than start 60 Minutes immediately, the network elected to do a two-minute news update about the Iranian drone strike on Israel. This pushed the start of CBS prime time programming two minutes later than it normally would've been, but the timings that CBS sent their local affiliates indicated that the final show of the night, Billy Joel: The 100th - Live at Madison Square Garden, would end on time (i.e. the prime time block would be four hours total as it would be on a normal Sunday, not four hours and two minutes) and affiliates wouldn't have to delay their late local news any further. This was wrong: the Joel special also ran two minutes over, but most local affiliates trusted the times CBS sent them, leading them to inadvertently cut off the final two minutes of the show, right in the middle of Joel's performance of his Signature Song "Piano Man". Again, the separate Pacific feed wasn't affected (it didn't have the news update before 60 Minutes so it ran as normal), but angry complaints in the rest of the country led CBS to schedule a re-air of the concert on April 19.
