Since we've been mentioning Scully in this thread, I've been doing a little reading. Never knew this about him, and thought it was pretty amazing...
On Saturday, June 3, 1989, Scully was doing the play-by-play for the NBC Game of the Week in St. Louis, where the Cardinals beat the Chicago Cubs in 10 innings. Meanwhile, Dodgers were playing a series in Houston and Scully flew to Houston to be on hand to call the Sunday game of the series. However, the Saturday night game between the teams was going into extra innings when Scully arrived at Houston, so he went to the Astrodome instead of his hotel. He picked up the play-by-play, helping to relieve the other Dodger announcers, who were doing both television and radio, and broadcast the final 13 innings (after already calling 10 innings in St. Louis), as the game went 22 innings. He broadcast 23 innings in one day in two different cities.
