The third episode the first season of My Little Pony: Friendship is Magic aired on October 29, 2010. It is called "The Ticket Master", and was written by Amy Keating Rogers and Lauren Faust.
The Story
Twilight is helping Applejack bring in some apples, when she receives a letter from the princess inviting her (plus one guest) to the Grand Galloping Gala, the social event of the year. Twilight is excited to go, and so are her friends--each for her own reason.
Applejack imagines that she could set up a stand and sell apples at the event, earning money for the farm. Rainbow Dash dreams of upstaging the Wonderbolts during their performance at the Gala, earning a spot on the team. Pinkie Pie wants to go because it's a huge party. Rarity wants to be a part of high society and meet (and marry) a prince. Fluttershy isn't so interested in the Gala, but is enchanted by the idea of the gardens that surround the dance.
Twilight can't decide which of her friends should get the extra ticket, and her decision isn't made any easier when each of them tries to do her favors to convince Twilight to give the ticket to her. Twilight, who just wants to get something to eat, spends the day avoiding her friends while trying to decide which of them she'll give the ticket to, and which she'll have to disappoint.
In the end, Twilight's friends see that they're making her unhappy by trying to get the ticket, and voluntarily give it up. Twilight, in turn, sends the tickets back to Princess Celestia, saying that if she can't go with all of her friends, she'd rather not go at all.
Surprisingly, Princess Celestia quickly responds to Twilight's letter by sending back six tickets--one for Twilight and one for each of her friends. She even sends one for Spike. Now, they will all be able to attend the Grand Galloping Gala together.
The Lesson
Twilight must make a difficult decision, and no matter what she decides, some of her friends will be disappointed. In the end, she chooses not to choose, and this works out well for her.
There are several lessons in this: first, Twilight learns that her friends won't abandon her even if she can't give all of them what they want; second, she realizes that making her friends happy is more important to her than attending the Gala--which is what her friends learned, too; third, minorly, she learns that she could have asked Princess Celestia for more tickets at any time--that she should be prepared to ask for help when she's in a difficult situation.
These lessons are all good, and we'll see some of them again, from different angles. The best and most effective lesson in this episode is the combination of the first two: that it can be better to make your friends happy even at some cost to yourself, and that they may feel the same way. I admire this dual presentation of the lesson.
My Opinion
This is the first episode after the initial story, so it's the first time we get to see how Twilight and her friends interact in Ponyville, absent lurking horrors. Unsurprisingly, their behavior isn't so different from how it was in the first episode, when they first met. Unsurprising, since a children's show like this can't be expected to do much character development, though a little disappointing.
Lack of complex character arcs aside, the episode is fun. It meets the standard set by the two-part introduction, containing a good share of comedy as Twilight tries to avoid her friends and another good share of pathos as she worries about who should get the ticket.
Details
The Grand Galloping Gala
You wouldn't guess it from the next few episodes, but this actually introduces a story arc that will be revisited later in the season, and which includes the season finale. In episode 14, "Suited for Success", Rarity will make dresses for each of the main cast to wear to the gala, and in episode 26, "The Best Night Ever", we see them actually attend.
Spike
In this episode, we learn that while Spike can eat grass or apples, like the ponies, he can also eat gemstones. We also see him acting a little childish, pretending not to be interested in going to a girly party like the Gala, but secretly wanting to go.
Angel Bunny
This episode marks the introduction of Fluttershy's pet rabbit, Angel. He's mute, but seems quite intelligent, and acts stern in contrast to Fluttershy's demure and pliable personality. He'll return in several future episodes of both the first and second seasons.
Money
It wasn't obvious in the first episode, since everyone seemed to be providing for the Summer Sun Celebration out of the kindness of their hearts, but Equestria does use money. Applejack imagines earning money to get some work done around the farm, and we may understand from this episode that Rarity has a business designing clothing.
I mention this because while the ponies are of indeterminate age, we can see that they must be young adults, since at least Applejack and Rarity are working to support themselves. This is notable, since children's shows very often have children as protagonists, and this is the first indication that the ponies aren't just particularly independent children or teenagers.