No, not Heaven's Gate. The Guiding Light premiered on January 25, 1937 on NBC Radio. Pending some last minute savior, the final episode will air on CBS television on September 18, 2009.
As of March 27, 15,638 episodes of the show have aired, which I'm reasonably sure makes Guiding Light the longest, most complex story that humans have ever told one another.
Back in my narrative theory nerd days in college, I spent a lot of time studying serial narrative, and the unusual demands that the form puts on the story. Nothing's been around as long as GL, and here's hoping that the producers can find some way to keep the story alive.