What does Flipping the Switch have to do with Geocaching? Here's what Geocaching.com has to say about it.
"On May 2, 2000, just past midnight, the U.S government discontinued its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide. Twenty-four satellites around the globe processed their new orders, and instantly the accuracy of GPS technology improved tenfold. Tens of thousands of GPS receivers around the world had an instant upgrade. Prior to this date, only the military had the ability to receive accurate GPS readings. Now, the world and all its wonderful people could pinpoint their precise location. For reasons unknown, this is often referred to as the flipping of the “Big Blue Switch”.
The very next day, a computer consultant named Dave Ulmer hid a black bucket in teh woods near Portland, Oregon. Along with a logbook and pencil, he left various prize items including videos, books, software, and a slingshot, then posted the coordinates online. Three days later, the container was located by Mike Teague.
Now, seventeen years later, geocaching has become a global phenomenon to get off the couch and get outside.