Celestia Hates the Sun, by Masterweaver
Zero-ish spoiler summary: What, the title wasn't enough for you?
A few thoughts: I went into this hoping for something on the level of "Princess Celestia Hates Tea," but gloomily predicting something more along the lines of "Every Other Pony-Verbs-Noun" story out there." The truth is that, while it's better than most, this falls closer to the latter end of the scale than to the former. The story starts out as a comedy, but then awkwardly jumps to sad-but-optimistic drama halfway through, in a manner I found jarring. The humor of the title (and subtitle, "The Solar Globe Is Loathed by Equestria's Eldest Princess") doesn't play nicely with the much more somber tone of the second half, especially considering that the drama doesn't get much in the way of a resolution.
Recommendation: I'm probably underselling this one a bit; it's got some good humor, and the drama is at least solidly rooted. But I'd only recommend this to those willing to put up with weak endings and poor comedy/drama melds.
The Cutie Mark Inspector, by Blueshift
Zero-ish spoiler summary: When Twilight doesn't get the respect she thinks she deserves, she does the unthinkable: she calls the Cutie Mark Inspector to town, to audit everypony's adherence to their special talents.
A few thoughts: This was disappointing to me because of how much better it could have been. The idea of enforced
Recommendation: This isn't the strongest of Blueshift's comedies, but it'll still probably appeal to fans of his. Those looking for more than surface jokes and whimsy will probably find that this comes up short, though.
Twilightning, by Bok
Zero-ish spoiler summary: After finding some incomplete notes on the subject, Twilight decides to complete and perfect an ancient form of transportation.
A few thoughts: First of all, allow me to boggle at the numbers; one out of every five people who read this story upvoted it. How do you even get that? As for the story itself, I found the idea more interesting than the execution. A lot of this story is simply Twilight going through the various steps involved in casting, recasting, and miscasting the spell, and while these are punctuated with a bit of comedy and some really nice worldbuilding, this story still drags when it degenerates into lists of "Twilight ____. Then, she _____. '_____' she thought, while ____ing," and so on.
Recommendation: Readers who put concept over construction should definitely check this out, as the spell and its history are very interesting.