A crime has taken place in Ponyville, and Octavia is the main suspect. Vinyl needs to find a defense attorney before her sister's trial begins. However, not a single lawyer agrees to help them. When everything seemed lost, one mare agrees to take on Octavia's case... the best defense attorney in Equestria: Lyra Heartstrings.

What do you mean we've been canceled!
AD17: I lost the ideas, so we're retconning to another possibility.
I'll kill you!
AD17: Gangnam Style.
Op, OPOP, OPA GANGNAM STYLE! Wait, where'd he go?

Following the Hearth's Warming Eve pageant, Twilight goes to Canterlot in order to research the historical events of Hearth's Warming Eve. However what she finds leads her on a journey across the sea and into uncharted northern lands. When she returns, she is visibly shaken and refuses to speak of what she saw to anypony. While over time she starts to recover, there are important questions left unanswered. What did she see on her journey and perhaps more importantly, what followed her back?

In search of gems to complete her ornate Nightmare Night costume, Rarity accidentally finds herself transported to a world where a holiday not unlike Nightmare Night is less an event than a way of life - and her friends soon follow in hopes of rescuing her. Or, to put things more lyrically....

It was some time ago, but not too long, you see?
In a place that perhaps you have seen on TV.

For this story spans places far from pedestrian,
Crossing spooky and dark with bright and Equestrian.

Now, you may be asking how that crossing was done.
If you are not, I'd say it's time you begun!

(An excellent talking-book version of this story can be found here.)

This story is a sequel to Past Sins

Side-story to Past Sins - Spike almost lost Twilight to a hangmare's noose, but now Twilight is safe and Nyx is a filly again. Normal life is returning. Still, Spike can't ignore the fact that Nyx just isn't the same as he remembers her. Her temper is more volatile, and, when she gets angry, all he can see is the rage-driven Nightmare Moon of legend.

And thus Spike has to wonder: Is Nyx truly reformed, or is she one bad tantrum away from calling herself Nightmare Moon again?

One by one, Twilight and her friends must come to terms with the consequences of being the Elements of Harmony.

These stories take place in the intervening time between Season One and Season Two,
with the exception of Ditzy Doo: Muffins, which takes place early in Season One.

The series continues in the sequel, Secrets and Lies.

Pony Psychology has a TV Tropes Page.

Twilight Sparkle and her fellow Elements of Harmony have faced down supernatural foes of the highest order, but sometimes the deadliest danger can come from places one would least expect. As Twilight is forced to bear a devastating secret, her efforts to keep the Elements together may well tear them all apart.
The plotline of the thrilling Pony Psychology Series continues with an exploration of deception, despair and Discord.
This series takes place between Season Two and Season Three.
Secrets and Lies shares the Pony Psychology Series TVTropes page.

Pinkie Pie is overjoyed when she meets a Pegasus who seems almost exactly like her.
She's fun, silly, and Pinkie's friends take an immediate liking to her.
What could possibly go wrong?

Translated into Russian here!

Ponies write hilarious, silly, sexy fan fictions about each other! FREAKING Ponies! (Each chapter is a 60-minute writing challenge train wreck. You've been warned!)

(...I am so, so sorry. XD)

Something I just couldn't get off my mind until I wrote it down. Be warned: the ponies in these battles really go off on each other. Almost exactly like it is in "Epic Rap Battles of History", except with less cursing. There's plenty of verbal bashing, though.

Vinyl Scratch is the DJ for most of these battles, and will be doing the all-caps commentary (except for the ones she's in, of course). OC tag because of slight self-insert.

I've heard that this story is better when read with someone else. You know, with each person doing one half of the rap battle?

List of Rap Battles (as per request)
#1: Twilight Sparkle vs. Rainbow Dash
#2: Pinkie Pie vs. Rarity
#3: Spa Sisters vs. Flim Flam Brothers
#4: Octavia vs. Vinyl Scratch
#5: Angel vs. Gummy
#6: Derpy Hooves (Ditzy Doo?) vs. Lyra Heartstrings
#7: Princess Luna vs. Discord
#8: Scootaloo vs. Pipsqueak
#9: Fluttershy vs. Screwball
#10: Apple Bloom vs. Diamond Tiara
#11: Trixie vs. Featherweight
#12: Silver Spoon vs. Spike
#13: Sweetie Belle vs. Queen Chrysalis
#14: Applejack vs. Carrot Top
#15: Bon-Bon vs. Lyra Heartstrings
#16: Twilight Sparkle vs. Rainbow Dash (rematch!)
#17: Big Macintosh vs. Shining Armor
#18: Iron Will vs. Photo Finish
#19: Gilda vs. Prince Blueblood
#20: Nightmare Moon vs. the Doctor (Doctor Whooves)
#21: Princess Celestia vs. Princess Luna
#22: Snips and Snails vs. Twist and Ruby Pinch
#23: Braeburn vs. Soarin'
#24: Zecora vs. Cheerilee
#25: Winona vs. Opalescence
#26: Derpy Hooves vs. Pinkie Pie
#27: Spitfire vs. Daring Do
#28: Princess Cadence vs. Queen Chrysalis
#29: Babs Seed vs. Lightning Dust
#30: Sunset Shimmer vs. Trixie *
#31: tba

Picture by Silversnow here on this site.

...should there be a 'sex' tag, considering some of the stuff brought up in the rap battles?