Cedric stops Harry on his way back up to [Gryffindor Tower], and gives him a hint about his egg - that he should take a bath with it, in the prefects' bathroom.

Christmas Day
Harry, Ron, and Hermione spend the day enjoying their presents, stuffing themselves over lunch, and snowball fighting with Fred, George, and Ginny. Finally they all head back up to the [dormitory] to get ready for the Yule Ball.
In the [dormitory] the fourth-year boys change into their [dress robes], with Ron mortified again at his appearance in his own.
At the Yule Ball
Harry meets [Pavarti] and they head down to the Yule Ball together. On the way in, Harry realizes that Hermione's partner is [Viktor Krum], and that she's made herself stunningly beautiful. Finally, he and the other champions lead the way into the [Great Hall], ready for the ball to begin.
In the [Great Hall] the champions head up to the top table, where they sit and enjoy dinner. Finally the dance begins, with even Harry and Ron managing not to make fools of themselves as the [Weird Sisters] perform. After the first dance, they sit (Ron sulking) and chat with various other students and teachers before finally deciding to take a walk outside.
Harry and Ron walk out of the Yule Ball and around the courtyard, where they overhear [Karkaroff] and Snape talking about something "getting clearer." As they keep walking, they overhear another conversation, this time between Hagrid and [Madame Maxime], in which Hagrid admits to being part-giant.
Back in the Yule Ball, Ron tells Harry the signifcance of Hagrid being part-giant, and they grudgingly watch the rest of the ball before heading back out.
Returning to the [common room], Harry discovers Ron and Hermione at loggerheads, with Hermione finally screaming that Ron should have asked her to the Yule Ball first, rather than waiting until the last minute.
Chapter 24 - "Rita Skeeter's Scoop" - In which past arguments are forgotten, and Hagrid is replaced as Care of Magical Creatures teacher when Rita Skeeter writes a defamatory article about him. HRH try but fail to visit him. HRH encounter Bagman in Hogsmeade, where Harry rejects his offer of help with the Tournament. Rita arrives and is verbally assaulted by Harry and Hermione, who then go to Hagrid's cabin, finding Dumbledore there. Together they persuade Hagrid to return to work.
The Part-giant