"Moody! How cool is he?"
- Fred Weasley
The fourth-year students gather bubotuber pus in Herbology, study Blast-Ended Skrewts with Hagrid, study Astrology in Divination, and Malfoy delights in pointing out that Mr. Weasley is in the paper again. In the argument that follows, Malfoy attacks Harry, but Moody turns Malfoy into a ferret, bouncing him around the Entrance Hall until McGonagall stops him.
Calendar and Dates
The chapter begins the morning after the students' arrival at Hogwarts and ends the same day, and since the Hogwarts Express runs on 1 September, we therefore know that the date is 2 September. From Ron's final line and the first paragraph of the next chapter, we know that the day of the week is Monday.
The fourth-year Gryffindors and Hufflepuffs have Herbology together as their first class on Monday morning. As their second class on Monday mornings, the Hufflepuffs have Transfiguration, while the Gryffindors and Slytherins who take Care of Magical Creatures have that class. The fourth-year Gryffindors who take Divination have it on Monday afternoons, while Hermione has Arithmancy and the sixth-year Gryffindors have Defence Against the Dark Arts.
Interesting facts and notes
Despite the chapter title, this chapter does not feature the first DADA lesson of the year (at least, not for the fourth-years, although it does for the sixth-years). (Of course, looked at a different way, Moody doesn't even appear in this chapter.)
This chapter gives us quite a few details about the timetables of the fourth-year students, at least for Mondays, as well as introducing bubotubers and blast-ended skrewts.
The storm had blown itself out by the following morning...
Which tells us that this scene is set the day after the preceding chapter's last scene - on 2 September, in other words.
"Today's not bad - outside all morning," said Ron, who was running his finger down the Monday column of his timetable...
And this gives us the day of the week. As we are about to see, Mondays feature two class periods between breakfast and lunch.
"Herbology with the Hufflepuffs..."
Since Herbology is a required subject for all fourth-years, we know that all the fourth-year Hufflepuffs are present in each of Harry's Herbology lessons, even if they aren't mentioned.
"...and Care of Magical Creatures...damn it, we're still with the Slytherins..."
Since Care of Magical Creatures is an elective for fourth-years, we don't know exactly which fourth-year Slytherins take the class. See further remarks below.
"Double Divination this afternoon," Harry groaned, looking down.
Divination is the only class the fourth-year Gryffindors who take it have on Monday afternoons, beginning just after lunch break and ending just before supper, so "double" appears to mean that it lasts for what would ordinarily be two class periods.
A large tawny owl soared down to Neville Longbottom and deposited a parcel in his lap - Neville almost always forgot to pack something.
As well as reminding us of Neville's poor memory, this shows us that the Longbottoms' family owl is a tawny. (This owl wouldn't be Neville's personal pet, since the owl must be staying with Neville's gran to have delivered a package from her so quickly.)
On the other side of the Hall Draco Malfoy's eagle owl had landed on his shoulder, carrying what looked like his usual supply of sweets and cakes from home.
This makes an interesting contrast with Neville, as well as suggesting a resemblance between Draco and Dudley.
...until they arrived at greenhouse three...
Harry's class first began working in greenhouse three during his second year; the mandrakes used to be kept here.
"Wear your dragon-hide gloves..."
These were a required purchase before Harry's first year at Hogwarts, and are now being shown to be intended for use as safety gear rather than ordinary winter clothing.
The Slytherins had arrived. The speaker was Draco Malfoy. Crabbe and Goyle were chuckling appreciatively at his words.
Care of Magical Creatures is an elective for the fourth-year Slytherins, so it's possible that some of them do not take the class; we have never seen a complete roll of the Slytherins in the class, so we don't know. However, we have been shown enough Care of Magical Creatures lessons to make a partial list.
"I mean, what do they do?" asked Malfoy. "What is the point of them?"
This is actually a fair question; Malfoy just happens to have an unfortunate manner in asking it. It also serves to illustrate the difference between Malfoy's attitude toward magical creatures - what can they be used for - and Hagrid's, which is that they're interesting in and of themselves.
"We haven't got him 'til Thursday!" he said in a disappointed voice.
Since the next chapter indicates that two days pass between this remark and the fourth-year Gryffindors' first DADA lesson, we know that the action of this chapter is taking place on a Monday.
Exceptional character moments
Rita Skeeter, who doesn't get Arthur's name right in her article "FURTHER MISTAKES AT THE MINISTRY OF MAGIC". So much for truthful and accurate reporting, when she can't even get an easy fact like that right...
"What - what are you doing?" said Professor McGonagall, her eyes following the bouncing ferret's progress through the air.
"Teaching," said Moody.
"Because I want to fix that in my memory forever," said Ron, his eyes closed and an uplifted expression on his face. "Draco Malfoy, the amazing bouncing ferret..."