"The Simpsons" attempted the massive feat over the weekend
Over the weekend, The Simpsons featured a three minute "live segment" that had Homer answering in live calls for audience members.
Due to the way that the time-zones work in the States, these live episodes usually get broadcast twice - once for the East Coast feed, and then again three hours later for the West Coast feed.
And, if you're curious, here's the west coast feed of that Simpsons episode:
While the segment itself is more of a curio-addition to the show rather than being anything of actual quality - if you found yourself laughing out loud at all, you're more generous to the jokes than they deserve - the live episode is the latest addition to a long-standing tradition among the best of the best of modern TV.
At one point, all TV shows were broadcast live, but with the advent of video and the vastly decreasing cost of show productions since then, very few shows attempt it any more.
There are obviously some shows that are always broadcast live - Saturday Night Live, The X-Factor, etc. - but when it comes to tightly scripted shows, where the drama and performances are as choreographed as any other part of the story, then "going live" can be something of a huge risk. One missed line, one missed cue, and everything can go wrong.
Back in 1997, NBC aired a live-episode of E.R. entitled "Ambush", which involved a PBS camera crew recording a day in the life of the hospital's emergency room. Below is a video comparing a segment of the episode, with the west and east coast feeds playing out side by side.
In 2005, NBC once again aired a live episode of one of their hit shows, Will & Grace. It was the first episode of the show's final season, and previously to filming the live episode, the cast had already shot and filmed the 2nd, 3rd and 4th episodes of the season, but in the interim, cast member Megan Mullally had injured her leg and was unable to walk without crutches, so the writers wrote into the episode's story that her character was unable to move without her motorized scooter as she was recovering from surgery on her webbed toes.
Unlike many of the other live episodes which appear to be done just for fun, in 2005 NBC broadcast a live episode of The West Wing with a more artistic merit in mind. "The Debate" featured Jimmy Smits and Alan Alda play their presidential candidates in a live debate covering hot topics in the current climate in America at the time. In fact, with candidate Matthew Santos, the show almost predicted Barack Obama's exact policies and campaigns three years before he was elected President.
That live episode of Will & Grace featured Alec Baldwin in a supporting role, who then went on to get an Emmy nomination for his performance, and who would appear again in another live episode of another NBC show, 30 Rock. Since most of the writers and producers stemmed from Saturday Night Live, and the characters work on a Saturday Night Live-esque live comedy show, it seemed like a natural progression for the show to attempt the live episode themselves. The 2010 episode, titled "Live Show" featured Matt Damon, Jon Hamm, and - in a moment of inspiration - Julia Louis Dreyfuss as Liz Lemon in the cut-aways.
The episode worked so well that the show returned to it in 2012, for "Live From Studio 6H", which featured Paul McCartney (for the east coast feed), Kim Kardashian (for the west coast feed), Jon Hamm, Donald Glover and Jimmy Fallon as a young Jack Donaghey.
American shows are not the only ones attempting the live episode, though. Coronation Street has three live episodes to date - one for the show's 40th anniversary in 2000, it's 50th in 2010, and ITV's 60th anniversary in 2015. The Bill broadcast two live episodes, one in 2003 on the show's 20th anniversary, and another in 2005 to celebrate ITV's 50th anniversary. Emmerdale broadcast a live episode for their 40 anniversary in 2012, Eastenders celebrated their 20th anniversary in 2010 and 25th anniversary in 2015 with live episodes, also. The last of which goes to show just how many tiny things can go wrong in the space of 30 mins.