To be REALLY precise, the DP began at the stroke of midnight on Saturday, October 11, 1997 with an episode of "The Gong Show. It ended a little more than six months later on Saturday, April 18, 1998 with an episode of "Child's Play".
IMHO, one of the few good things about the DP was that $20K Pyramid got some air time...
It was quite the interesting time once the dark period's clouds began to lift - GSN started running promos for shows like "Card Sharks" and "Match Game" on April 1, prompting people to post to a.t.g-s where their claims about the commercials were laughed at, being that it was April 1.