In order of plausibility, the term Stargate refers to:
A.) A TV series about what would happen if MacGyver fought space aliens.
B.) A military undertaking that used psychics as intelligence gatherers.
Over the course of 20 years, (and 20-million dollars) the U.S. Army employed no less than 22 full-time psychics. This all started when command heard rumors back in the 70s that the Soviets were using psychics for military intelligence and, rather than chalking it up to Vodka and Babel-fish quality translation, they decided to run with the idea as well.
The idea was to use said psychics for something called "remote viewing," which is the ability to telepathically see information about distant locations. Or, more accurately, it is the ability to lie about seeing information about distant locations while holding your hands to your temples and wearing a sequined shirt.
To test their psychics, the military placed them in a room all alone and gave them a set of coordinates; the psychics would tell the military what resided at those locations and then satellites would confirm or deny the predictions. One psychic viewer, Pat Price, said that he could clearly see a military base at his location, and that the base had a crane. Aaaand that was enough for the military!
Rather than assuming this "psychic" might have guessed that the military was interested in military-related places like military bases, and that they probably needed cranes to lift their heavy things, they gave Mr. Price the benefit of the doubt and subsequently used that precedent to justify appropriating government funds in order to pay for magic shows.
Pat's actual drawing of the crane, which he probably saw on his way into the same base where he took the test.
If a psychic was wrong (which--surprise!--happened a lot) the official policy was not to tell them, because it might lower their morale. Who knew the U.S. Military had an official policy about hurt feelings, and further that said policy was to avoid them at all costs?
But they did question at least one prediction: That crane at the Russian military base. They asked Pat why he didn't see a set of oil derricks as well, and Pat responded that the oil derricks were disassembled. The agents got a satellite to take some new, updated pictures of the base just to give Price the benefit of the doubt, and found that the derricks were indeed still there.
So he gave vague information that anybody could have guessed at, got the only verifiable answer wrong, and still kept his job for 20 years? Yeah, that sounds about right for a federal employee.
The United States just plain doesn't like Cuba. And it's easy to see why: It just hangs out down there, suspiciously close to Florida's personal space, looking like it's about to reach out and touch America's Dong at any minute. That just doesn't sit right with us, man.
From 1962 to 1964, the CIA compiled an exhaustive collection of plans to help topple Cuba. Aside from the obvious "country-wide wedgies" and the sinister "tell South America they've been talkin' shit," there were far more disturbing ideas under consideration.
One of the most prominent plans was Operation Northwoods, a proposal to create terrorism on American soil, blame it on Cuba and thus give the U.S. a reason to bomb the living shit out of Castro.
There are nine separate, documented suggestions for home-grown terrorism plots, and they range from blowing up an American ship in Guantanamo Bay, to sinking a boatload of Cuban immigrants en route to Florida. One instance even proposed that John Glenn's rocket should "mysteriously" explode shortly after launch, and that the entire incident be blamed on Cuba. This was probably scrapped when they remembered the memo from Project A119 that implied all astronauts were walking atomic weapons.
"Them cats we fuckin' with put bombs in your mom's gas tank" - Official report advising against attacking Glenn by the esteemed Professor B.I.G.
We should also reiterate at this point that these were not fringe groups we're talking about: The entire operation was approved by all the Joint Chiefs of Staff.
Nobody saw a problem with it--except President Kennedy, who thankfully realized the implications of Northwood (i.e. that punching yourself in the face as an excuse to punch somebody else in the face was not a valid military strategy) and ultimately rejected it. Most of the documents involving Operation Northwoods were de-classified in 1997, and are now serving out their life-sentences as conspiracy theorist porn all across the Internet.