Lifelines

Host: Each of the buttons on the Help Vest represents a different Lifeline that you can use, should you need it.
Contestant: It's burning me!

Host: It's burning you because it's filled with sensitive electronics that could help you win one million dollars! You can Text a Teacher, Borrow the Truth, Accuse a Parent, or Open a Trap Door down to the Clue Chamber where you just might have to face... The Commissioner!! (dramatic orchestral sting)

—Mad TV sketch "One and a Million".

Rampant in TV game shows of the past decade since Who Wants to Be a Millionaire? debuted and essentially became the template for all big-money games that surfaced thereafter.

Basically, in any game show with only one contestant trying to win a massive prize, he is given assists that he can use at any time to aid his chances of winning. Generally, it's to stop players from bailing out at the first sign of trouble, as almost all of these shows include a rule where the contestant loses all or most of their winnings if he gets so much as a single question wrong.

Examples of Lifelines include:

Game Shows

• Are You Smarter Than a 5th Grader?: Players used "Cheats" that they could use that would incorporate the onstage kid's answer; "Peek" (look at the answer, but not be committed to it; the contestant had to answer, however), "Copy" (lock in the kid's answer as their own), or "Save" (get credited for a right answer if the player was wrong but the kid was right).
• Cash Cab uses "Shout Outs": one where the passengers try to get the right answer from someone on their mobile phone, and another where they flag down a pedestrian to supply an answer.
• British game show The Cube offers two Lifelines: "Simplify", which makes the current challenge easier in some way (increasing the size of the target, for example), and "Trial Run", which allowed to player to practice the game once before deciding whether or not to risk it.
• Don't Forget the Lyrics: Had assists called "Backups": One allowed you to see three choices of the correct lyrics, another filled in any two of the missing words that you wanted, and the third allowed you to bring up a friend to sing the lyrics instead. The daytime version of the show only uses the "three lines" Backup available.
• The ABC quiz Downfall had contestants answering questions as the prizes they tried to win were sent down a conveyor belt off a 100-foot building. If elimination seems imminent, they can push the "panic button" in front of them, which resets the belt (without the prizes), and places either a personal item or a loved one on the belt in front of the cash prize for that level. (The loved one can help answer questions up until they drop off the belt.)
• Greed: A Freebie was awarded to teams who reached the $200,000 question, at which point each question had four right answers from at least six choices. The Freebie removed one wrong answer from the choices, and ended up being used on the next question almost every time due to the heavy use of surveys and other subjective material for those questions.
• Identity: Had three helps; "Tri-dentity", which reduced the number of options to three; "Ask the Experts", which allowed a panel of experts on body language to weigh in, and "Mistaken Identity", which was essentially a free miss before the player lost it all. Of course, if there were only two identities left, you couldn't use it.
• The extremely short-lived It's Your Chance of a Lifetime also had helps called "Second Chances". One reduced the question to a three-way multiple choice, while the other switched the question out for one from the contestant's pre-selected favorite category. Contestants that reached the final three questions were allowed to use either one of these a second time as a "Last Chance".
• Million Dollar Mind Game had its own set of three which could be used after the team captain locked in an answer. One allowed the team to throw out the question and replace it with a new one. The second allowed any member of the team to override the team captain's answer at the last minute. The third gave them 30 seconds of extra discussion time (and unlike the below, the questions were designed so that the team might actually need it), at the end of which the team captain could give a new answer to override the original one.
• Million Dollar Money Drop offers the lamest of the bunch by a longshot: a "Quick Change", which allows the couple an additional 30 seconds (after their inital complement of 60 expires) to move their money onto a different answer. Considering that they still have to place all their money on the drop zones while leaving one empty, and that all the questions were from the Greed school of surveys and magazine opinions instead of objective facts, all it did was give them more time to think about the question.
• One Versus a Hundred: During the game, the One could "Poll the Mob" (see how many of them gave a certain answer), "Ask the Mob" (have two of them explain the reasoning for their answer), or "Trust the Mob" (automatically lock in the answer they most commonly gave).
• Set for Life: Done in the form of another person, called the "Guardian Angel", being sequestered in a Sound Proof Booth during the game and making the same play-or-stop decisions that the contestant made. If the Guardian stopped, the game ended, and anything the contestant did after that point was ignored, whether they won the top prize or blew it completely.
• 21: In the 2000 revival, contestants were allowed to ask for a "Second Chance", in which a friend was brought on stage to offer an answer to the player. If the friend was wrong after the player used the Second Chance, however, the player would get two "Strikes" instead of one (three Strikes meant you lost automatically).
• A possible Ur Example that makes this Older Than They Think, the 1979-80 CBS game Whew allowed the Charger to call for a "Longshot" if time was running short, which stopped the clock and sent them to Level 6 (the top of the game board). The catch was that doing so allowed the Blocker to place a secret Block on one of the three amounts up there ($250, $300, or $500) to go along with the Block that almost certainly was placed up there at the start of the round. If the Charger found a blooper and corrected it, s/he won; anything else, and the Blocker won.
• Who Wants to Be a Millionaire?: Trope Namer. See the article for all the Lifelines.
• Winning Lines: During the "Wonderwall" bonus round, the contestant could use a "Pit Stop" to freeze the clock for 15 seconds while he refamiliarized himself with the answers on the board. He could also pass on two questions in the U.S. version.

Others

• Video game example: L.A. Noire. When talking to/interrogating people, you can use "intuition points" to remove one of the three questioning options (Truth, Doubt, or Lie) or see what other players selected for that option.