She's Spitfire - trick flier extraordinaire, commanding officer of the Wonderbolts, an Equestrian hero, and a role model for everypony that lays eyes upon her. For that reason, the fact that she smokes is something that the 'Bolts try to keep hidden - it protects her image, their image, and protects the youth of Equestria from her bad habit.
Because, as all of Equestria knows, smoking is bad.
Her secret remains contained within the Wonderbolts, to the point that many of their newest recruits don't even know about her habit until they join. So when they find out, well... they all have their own reactions.
And then there's her faithful executive officer, who hates her habit but is always there to back her up, in public or private. Because Soarin's her XO, and that's what an XO does.

This story is rated as 'Teen' due to the somewhat mature topics - particularly tobacco use.

Some Canterlot entertainers aren't just musicians... and some ponies fall in love with them anyways.

When one of Equestria's most popular cellists appears at Twilight's birthday party, it's just another gig for Octavia, but a shock for Twilight and the rest of the party-goers. She arrives, wishes Twilight a happy birthday, wows them with her beautiful music, wows them with her musical beauty, and doesn't leave until after everypony else has left. So when a few ponies suggest that this 'entertainer' might be more than just a musician... some eyebrows are raised, but nothing more. Twilight is beyond reproach, after all, and Octavia can earn her living however she wants. When she sticks around Ponyville, however, it becomes a slightly different story - Twilight is romantically-naive, after all, and Octavia is... most certainly not.

The romance of Twilight Sparkle, Celestia's protege, and Octavia van Clef, Canterlot's most famous entertainer.

Rated 'Teen'. Per FimFiction's rating guidelines, this story contains some 'more adult themes', but has no 'graphically adult content'. Rated primarily for sexually suggestive material, but also (in later chapters) alcohol use and adult language.

A violent, unexpected thunderstorm wakes Rainbow up in the middle of the night. Unable to do anything about the storm but unable to sleep, she has nothing to do except lay in bed and think. Ponies, Ponyville, her job, her friends, and the differences between Loyalty and Honesty - not all of them always make sense.
A short swim through Rainbow Dash's stream of consciousness.

Rated ‘Teen’ for language.

It's been a thousand years. Princess Luna is returned, and the castle staff must scramble to see that she has servants to attend to her needs, and just as importantly, that they look the part. Of course, it turns out that it's rather difficult to find competent servants on such short notice. A hooffull of servants are chosen based on their appearance and duties, and are assigned to serve the Moon Goddess as personal retainers until more suitable replacements can be found. When coloring, Cutie Mark, and chance coincide, one of the castle's junior stewards is thrust into a role any loyal servant ought to jump at: Lunar Hoofservant. Unfortunately for Nightlight, Princess Luna is far more demanding than her older sister, and being her servant means contending with an unforgiving goddess who demands nothing short of perfection. Furthermore, somepony must be responsible for the inevitable failure. The duty of "Royal Hoofservant" just might be synonymous with "Royal Scapegoat."
Saddled with responsibility far beyond his post and expected to fail, Nightlight has no choice but to quit his post or to become the servant that Luna needs. This is the story of a pony's development from colt to stallion, and from servant to leader.
Thanks much to DirePony for the editing and story direction he's graciously provided me.
Rated 'Teen' for alcohol use, mild innuendo/sexual references, and pony-swears.
Not based on the (excellent) sci-fi novel of the same name by Robert Heinlein.