Combined with Dr. Strangelove, Russia has a real automated system: the Perimeter system, also known as the Dead Hand. Officially, it is turned off in peacetime and only turned on in times of crisis, but is said to remain fully functional and able to serve its purpose whenever needed.
Hackers created programs to dial numbers in an area to search for modems as shown in the film. These programs became known as "wardialers", though these already existed before the film and were commonly called "demon dialers." The practice evolved into "wardriving," looking for open Wi-Fi networks.
Genius Bonus: The guard's discussion in the beginning involves someone he knew who grew plants while chanting "om mani padme hum", which is a Sanskrit mantra also known as "the jewel of the lotus flower".
Life Imitates Art: A common "problem" for military simulations provides a simultaneously amusing and disturbing example. Machine learning systems tasked with simulating cold wars frequently come to the same conclusion that Joshua did: the whole situation is a waste of resources, and deescalation is the only logical solution.
Word of God says Barry Corbin ad-libbed the line "I'd piss on a spark plug if I thought it'd do any good!"
The jeep accident as David, Jennifer, and Falken ram through NORAD's front gate was unintentional; the jeep was meant to keep driving right to the base itself and not flip over. John Badham left it in and filmed a shot of the trio running the rest of the way to the base.
Unintentional Period Piece: The then-contemporary theme of Cold War nuclear panic definitely dates this film to before The Great Politics Mess-Up, as does its treatment of then-emerging computer technology (to early in The '80s). And of course there's the technology itself: dialing into remote systems with an acoustic-coupler modem looks positively quaint in the era of broadband internet, as do supercomputers with graphics that the most basic of modern PCs would put to shame (or even a computer of 1983). (The acoustic-coupler modem was already outdated in 1983. It was just there to be visually interesting.) The lax attitude to computer security is almost a textbook example of how not to do things these days, though to the irritation of IT people the world over, people still insist on writing down passwords to this day. And this being The '80s, there's the obligatory video arcade scene. Not to mention the way Lightman did his research on Professor Falken: going to the library, looking him up in the card catalog, reading books and microfilms; something that one can do today by typing it into Google.
The original writer of the story said that he wanted Falken to be played by John Lennon, and Lennon was reportedly interested in the role. Lennon was killed before filming began.
The original director was Martin Brest, but only two of his scenes made it into the movie: David and Jennifer's meeting with Jim and Malvin, and David calling Jennifer at a phone booth in the middle of nowhere.
WarGames: The Dead Code
Dawson Casting: Amanda Walsh as Annie. She's 27 at the time of shooting and it shows.
Fake Russian: Vlada Vana, from Czechoslovakia, playing Ivan, the former Soviet astronaut.
The Other Darrin: John Wood played Falken in the original. In the sequel, he is played by Gary Reineke.