On Sunday, February 25, 1996, the Space Shuttle Columbia deployed an experimental tether into orbit. The experiment was called the Tethered Satellite System (TSS- 1R) and it's purpose of this was to attempt to generate electricity by utilizing Earth's magnetic field.
Unfortunately the tether broke so the experiment was not a success, although approximately five hours of data were recorded.
What really made "The Tether Incident" famous was the appearance of many unidentified flying objects (UFOs) clearly visible in the NASA footage. Conspiracy theorists rejected NASA's explanation of space debris and ice particles, while conspiracy debunkers pointed out that the UFO theory doesn't stack up. For example, if the UFOs were as big as the conspiracy theorists claim, they would have been clearly visible from the ground.
NOTE: The footage above begins with a text title which has been added by someone obviously not from NASA. I do not personally agree with the text, but this is the only version of the footage I have been able to find. The rest of the footage is apparently genuine NASA footage (public domain).
Date: February 1996
Credit: Original footage by NASA, additional text title unknown