ER is a medical drama on NBC, created by Michael Crichton and executive-produced by Steven Spielberg, who actually didn't have anything to do with the show after the first year or so. In its final years, it became the flashpoint of a nationwide controversy involving the artificial extension of a television show's life.
Initially a vital and compelling drama, ER slipped into a coma upon the departure of original cast member George Clooney, and subsequently was pronounced brain dead when lead Anthony Edwards left the show. Even as ratings flatlined, producers and network executives worked furiously to keep the series alive with regular transfusions of new cast members, with ever-decreasing success. Tragically, ER soon existed entirely on life support, populated by replacements of replacements of original cast members. A growing movement called for NBC to pull the plug on the show, allowing it to die with dignity -- which the network eventually did in April of 2009 -- but an opposite and equally vocal faction condemned that move as murder, fervently believing that the show may still regain consciousness.
Senate Majority Leader Bill Frist, having seen a videotape of an episode from the show's 11th season, recently stated that in his expert medical opinion, the show seemed "very much alive" and "responsive to stimuli."