Events in Live Action Television that are not possible. only list examples that fit this description
How I Met Your Mother has an episode in which Barney Stinson references this trope literally, claiming to have transcended the impossible to a point where the impossible and the possible meet: The Possimpible.
MythBusters deconstructs this trope. They demonstrate what is possible and what is not.
Buffy the Vampire Slayer states that only one slayer can exist at a time; when one dies, the next awakens. That's what the Council decreed. The show skirts this trope with clinical death which creates two slayers, but doesn't fully play it straight until Willow decides to break the rule and wake up EVERY possible slayer.
Subverted in Star Trek. Warp 10 is said to be the highest warp and it is; the only thing that increases is the speed of Warp 10. However, no matter how fast it becomes, its still Traveling at the Speed of Plot and therefore not really changing at all.
Played straight in Star Trek: Voyager in the episode in which the warp ten barrier is introduced. Voyager reaches Warp 10 and exists at every point in the universe, but also causes the humans onboard to evolve into salamander-like creatures. Normally with something like that we say it's Better Than It Sounds, but that one wasn't, and the episode has since been officially disowned by the writers.
There were two distinct warp scales used in Star Trek. The one that was used in original series was a cubic function (velocity = warp factor cubed x the speed of light) and had no upper limit. The one used from Star Trek: The Next Generation on is hyperbolic and made warp 10 equal to infinite velocity—even if you were traveling at warp factor 9.999999...., you would still be infinitely far from warp factor 10 in this scale.
Pawn Stars Rick buys a car for Old Man's birthday and needs it restored. It's estimated that it would take 6 to 8 months to restore the car, and that's if Rick the restorer didn't have any other jobs the entire time. Rick needed it in three, and somehow, it was done in three. While Rick's shop worked on other projects.
Seinfeld Parodied as part of Jerry's ridicule of Kramer's claim that Keith Herandez spat on him. He traces the imaginary path of the spittle which involves changing directions and pausing in mid air. "that is one magic lugee." The point being to illustrate how impossible it was for the event to happen in real life.
Austin & Ally has a plot where Dez deep fries an entire restaurant, including the tables and chairs. How he made an ordinary deep frier do that is a mystery.
Xena: Warrior Princess features numerous Gods, (of Greek, Norwegian, Turkish and Roman orgins, among others) which like any Gods, are immortal. This is a universe where Immortal Life Is Cheap. For the first five seasons, it doesn't matter what you did to a god, they would not die. However, in the Season 5 finale, Xena gains the power to "Kill the unkillable." In the span of 12-15 hours after gaining this power, Xena had killed Poseidon, Hephaestus, Deimos, Hades, Artemis and Athena, with no signs of slowing down.
Xena also features the title character being impregnated by the redeemed soul of her archenemy, Callisto. When she discovers she is pregnant, she expresses the impossiblility of the situation, by slamming the doctor into a wall.
Meta example from Doctor Who: in the episode Doctor Who NS S2 E4 "The Girl in the Fireplace", the Doctor makes a tremendously grand entrance — smashing through a mirror, on a white horse, into an actual Versailles ballroom. After much deliberation, this was deemed literally impossible to film by the production team. (Versailles does not allow horses into their ballrooms, for one.) When they told Steven Moffat, he broke down and cried like a child, and so the production team decided to film it anyway.
