good idea fairy cut-off date (GIF-COD) 

Military term: The absolute, iron-clad, no-bull date/time when any visit by the good idea fairy will not be tolerated by anyone for any reason. For most reasonable people this is not later than the time an operation plan or order is published. For senior officers and politicians this is only a hypothetical moment that never arrives.

"The good idea fairy cut-off date (GIF-COD) for this operation is the date we issue the order to the units," said the Commander. "I will personally kill anyone who suggests anything after that."

and;

"The attack was going well until the good idea fairy struck. They failed to establish a GIF-COD.

good idea fairy cut-off date (GIF-COD) by Baghdad Bob May 2, 2006

That was a bad idea 

Most commonly used after a night of hard drinking.
or
after you get pulled over by the cops

Waking up in someones else's bed, ussually an ugly person, you thought was hot the night before.

Unlucky Guy = Jesus Christ did I really do that? That was a very bad idea.

Guy 1 = Well that was a bad idea
Guy 2 = Nuh, you think?
Guy 1 = Maybe doing doughnuts in a cop shop WAS a bad idea.
Cop = Ok you two, your coming with me
Guy 1/2 = Fuck

That was a bad idea by Jonno8825 January 2, 2009

Bad Idea Bears 

characters from the play Avenue Q : the Bad Idea Bears are the ones that suggest that you have drinking contests the day before that important interview.... Bad Idea Bears are really just our inner (bad) kid, goading us on into STUPID ideas!

"Last night? I don't remember anything after a visit from the Bad Idea Bears.... I remember them saying a few lines of coke 'wouldn't hurt just this once'..."

Bad Idea Bears by TheGoddessMaria October 31, 2009

prestige worldwide idea 

When you have an idea that is so amazing and ingenious that it feels like a lightning bolt just hit the tip of your penis.

Guy1: Dude, I just had a prestige worldwide idea! We should totally...

Guy2: OMG, yes!

Guy1: My penis is tingling.

prestige worldwide idea by NightHawk Dragon XXX December 26, 2011

no idea

The effect of not having any clue of what is going on, or what is happening. May also be a reference to inquire one's ability to think.

I have no idea why I can't believe it's not butter!

no idea by The Cynical One March 20, 2009

The idea school

A school for those who learn better through projects, or to be honest, kids who just don't want to do homework or study for tests. Most of them have gotten kicked out of another high school, and about 60% are gay. Walking the halls of this school you will probably see people randomly doing the gay hand flick to each other, people listening to music and ignoring everyone else, and people with newly dyed hair.

Oh you go to The idea school, no wonder you go by they/them pronouns

The idea school by caseykk717 December 3, 2021

dim idea

The non-sarcastic equivalent of a bright idea. Basically, an idea that is obviously stupid and not very bright/smart.

Joe had the dim idea to try to drive 500 miles in a car with a bad transmission. As a result, the car broke down and his ass got stuck in the middle of nowhere.

dim idea by Kellie Crosby March 14, 2008