The day friendship becomes extinct. :3

I’d love to see Celestia make a giant hourglass that flows backwards so people stop asking her what they’re all “counting down” to.

Silence will fall when the question is answered.

Celestia’s birthday.

THE FALL OF EMPIRES.  
THE RISE OF THE REPUBLIC.  
THE END OF FOREVER.

Serious answer: they’re old fixtures simply used for timekeeping, having been around before clocks and now both antiques and still reasonably useful. Plus Celestia likes their style.
 
Wild-eyed raving overthought answer: As immortals, Celestia and Luna have serious difficulties existing at the same timespeed as other ponies, and were known in prior years to speed up to mania, or spend years moving glacially, almost catatonic. (Their sister usually compensated to keep the sun and moon moving at a steady pace during these times.) Having an abundance of hourglasses performing a task at a steady, constant rate, visible at many points around Canterlot, keeps them in phase with normal ponies. Their obsession with timekeeping instruments is one reason so many ponies develop hourglass cutie marks.

Well, they were counting down to December 21, 2012. Guess they’ll need something new now.

The hourglasses are counting down to when they need to be flipped.  

They’re counting down to bad wolf.

Colgate.

The sands of time?

hour glasses are like clocks, and the clock is ticking Twilight the. clock. is. ticking.

What? A mare cant have a fetish for massive hourglasses?

When Celestia and Luna change shifts.

Epic Foreshadowing?

INB4 Doctor Who comment

If I were to guess, I’d say “the next hour”. That’s what hourglasses are for, after all.

Maneighyan Apocalypse

DOOOOOOOOOOOMM!!!!!!!!

Series Finale :[