Film fans, here's a curly one for your Friday: Pick the greatest film of all time. Just the one. Oh, by the way, there's no takebacks and everyone gets to judge you and your pick. Cool? Cool.
I'd be happy to wager that right now your brain is hurtling back through time as you ponder your answer.
Memories of movies you've seen and enjoyed flit past in a hazy blur of popcorn and choc-bomb ice creams as you attempt to balance a film's entertainment value against their worthiness factor.
Remember, we're looking for the greatest film here. Choose carefully. Tread lightly. Don't fluff it up ...
No doubt you paused briefly on cinema's usual suspects - 2001: A Space Odyssey, Vertigo, The Godfather, Predator etc - before assessing, weighing up and discounting each one as you journey backwards through the annals of moviedom.
And while those few flicks I listed are all absolutely amazing, could any of them really be labelled "the best"?
Hmm ... It's a big call.
But just as all roads lead to Rome, all "best movie ever" lists stand under the shadow of a masterpiece - Orson Welles' unarguable, indisputable and unbeatable 1941 classic Citizen Kane.
It arrived on the scene as the greatest picture of all time and has swatted away countless challenges to the throne in the 75 years since.
This is a problem. Each year thousands of movies are released - everything from big-budget blockbusters through to no-budget straight-to-TV titles - and none of them tends to make the cut.
Well, it's hardly a surprise people aren't picking Suicide Squad or Bad Moms as their "greatest film ever" pick. But has cinema got steadily worse since 1941 or are we - collectively - stuck in a rut of judgment? Are we missing celebrating the new modern classics because we're blinded by the rosebuds of the past?
The BBC recently addressed this very problem after hitting a wall of familiarity back in 2015.
Having polled 62 international film critics to determine the 100 greatest American films of all time they discovered only six films made since 2000 had been deemed good enough to make the cut.
Of these six the highest ranked was David Lynch's Mulholland Drive, which was released in 2001. It came in at number 21, meaning no film made in the last 16 years cracked the Top 20.
In an attempt to remedy this malaise the Beeb this year asked 177 critics to name the best films made since 2000. This had a triple whammy effect.
Firstly, it neatly culled every movie made last century from contention. Secondly, it highlighted great titles that were constantly overlooked in favour of evergreen classics like Casablanca or Taxi Driver. And thirdly, it meant that movies that ordinary people - as opposed to film scholars, historians and enthusiasts - had actually seen were given a shot at the title.
So while fun and beloved blockbuster romps like Guardians of the Galaxy didn't chart, the extraordinary action of last year's Mad Max: Fury Road exploded into the Top 20 at number 19.
I suppose the list could be classified as a reboot. But as a talking point, or start to a conversation, it's superior in just about every way possible. Not least because now more people can participate.
In this day and age pictures like The Social Network (number 27), WALL-E (no 20) or Inglourious Basterds (no 62) are way more accessible and familiar to modern audiences than old school fare like last year's charting movies, Singin' in the Rain, Rio Bravo or Gone with the Wind.
Taken in this context it's somewhat predictable that Lynch's unpredictable Mulholland Drive would move into the prized number one spot. But it's entirely pleasing to see Hayao Miyazaki's brilliant animated masterpiece Spirited Away hitting number 4. And while I don't agree with every film on the list - Boyhood, Pan's Labryinth and A.I. Artificial Intelligence weren't all that and a bag of chips imo - I still gotta admit that, all up, it's a pretty stellar selection.
It's certainly hard to argue with.
Oh, and out of interest, what film did you end up picking as your greatest of all time? More importantly, when was your greatest film of all time? Interesting, isn't it?