Flim Flim-Flam telling off Diamond Tiara and standing up for his brother in chapter 20:
"You can say whatever you like about me. I've been bought and paid for, lock, stock, and cider barrel. But my brother never sold out. He never auctioned off his self respect for your witless husband's golden promises only to be put on ice for five long years. You don't get to talk about him that way, you stuck up, spoiled little snot. And now, after all these years, I understand the value of what I gave up. Well, I'm returning the unused portion for a full refund. Consider this my two weeks notice!"
Also in chapter 20, Celestia shows exactly why the bits stop with her. After the excitement has died down, and the specifics of the race decided, she offers royal sponsorships for both companies—the race is normally pegasus only—and, in the interest of fairness, offers to be the sponsor of Professor Destiny's team. She graciously accepts his apology for earlier words... then promptly has the whole group arrested for disrupting the event.
In chapter 25, Soarin and Pipsqueak teaming up with the Wonderbolts to dispel the Flim-Flam brothers' smoke-screen.
In chapter 26, Twilight decides she's had enough of Apple Bloom's anger over her and Pip breaking up and confronts her about it. When Apple Bloom scathingly retorts that Twilight doesn't understand love, Twilight responds that while she doesn't have the deep understanding of love that Cadence does, she observed love in enough forms to know that in the end, Apple Bloom's "love" for Pip was purely superficial, and her anger and jealousy is just a childish tantrum.
What makes it better is how maturely Twilight handled it. It could have been easily a low blow for Twilight that she's never had a special somepony, but she shrugs it off wonderfully, showing how you can be content with your life even without romance.
Soarin' fighting off the LaFish brothers to give Pip a chance to escape in chapter 28. Even though he's still somewhat out of shape compared to his glory days, he still kicks ass, and doesn't even realize he's been hurt until after the fight's over.
As Baron Redtail himself puts it: He may be retired as a Wonderbolt, but he still flies like one and fights like one. Given the Baron's aloof nature, this is quite the compliment.
Gets even more awesome when one considers that Soarin' is still slightly overweight and was recovering from his fight with the LaFish brothers at the time, whereas Shootin' Star is in his prime, and Soarin' still won without contest.
When Applejack confronts Baron Redtail over his challenging Soarin' to a duel, the Baron's Ninja Maid tries to fight her, only for AJ to buck her across the room and into unconsciousness without even breaking stride.
Chapter 32 gives an awesome moment to Luna. Basically, she uses her years of Nightmare Night experience to get the LaFish brothers to sing like canaries. And it is glorious.
You have to give Diamond Tiara credit for simply refusing to die in the Badlands, not stopping until she finds civilization and shelter.
The Royal Guard battalion pursuing the Flim-Flams not only not letting the sandstorm get in their way, but flying right into it and breaking it apart, scattering the dust devils in the process.
Otto gets a villainous one when he saves the brothers from the Royal Guard, using Poison Joke pollen to incapacitate most of them. Then he gets another one when he finally has enough of them when they decide to continue the race, quits, and heads for Mexicolt.
Rarity getting even with the Ambrosia purser who constantly accused her of being a changeling, by judo throwing him, and then stating that she'll be taking her future business elsewhere, as well as telling all of her many associates to do likewise.
Fancypants neatly shooting down Blueblood's attempt at Karma Houdini. Blueblood puts on a show about being devastated at Diamond Tiara's disappearance, until he's back in his private suite, where he starts celebrating... only to find Fancypants waiting for him, wishing to discuss the whole situation with Chrysalis on behalf of Royal Blue Line's shareholders. Blueblood deflates nicely at that.
Soarin's duel with Baron Redtail. Not only does the retired, and still slightly out of shape, Soarin hold his own against Proud Warrior Race Guy Redtail, but he actually wins, by riling Redtail up in order to keep him from noticing that Soarin's leading him into a terminal dive.
After the Flim Flam Brothers crash into Shining Armor's shield spell and accidentally cause the Ambrosia to crash the real winner of the Pegathalon arrives. Who is it? Rainbow Dash. She performs a Sonic Rainboom to arrive as quickly as possible, to make sure everyone's okay. It actually takes a moment for her to realize what's happened. Doubles as a Crowning Moment of Funny.
When Twilight hears about the above crash, she becomes worried about Celestia, so she teleports the balloon that she, Rarity and Apple Bloom are on all the way to Canterlot. While it isn't stated how far this is, the city wasn't even in sight yet, meaning it was at least several miles. She's really stepped up her game.
Of course, it turns out she only teleported the gondola and left the balloon itself behind. Fortunately, Celestia shows up in time to catch them before they hit the ground.
Rarity single-handedly shooting down any complaints the Cloudsdale city elders might have over the flight harness' existence by stating how much money they'll potentially make from all the unicorn and earth pony tourists who'll now be able to reach the city.