Detentions

"That's how it is at Hogwarts. Copyin' lines! What good's that ter anyone? Yeh'll do sommat useful or yeh'll get out."
     -- Rubeus Hagrid (PS15)

"It's just a pity they let the old punishments die out...hang you by your wrists from the ceiling for a few days, I've got the chains still in my office, keep 'em well oiled in case they're ever needed..."
     -- Argus Filch (PS15)

detentions
points

In years past, punishments for rule-breaking at Hogwarts were severe indeed. Filch speaks longingly about being allowed to suspend guilty students by their wrists from the ceiling for a couple of days (PS15). He still begs Dumbledore for the chance to hang a student up by the ankles (CS8) and keeps a set of chains all polished up and hanging from the ceiling in his office. Molly Weasley recalls the night when she and Arthur were caught out of their common room taking a moonlight stroll; she escaped capture, but Arthur was caught and punished by the caretaker, Apollyon Pringle, and "still has the marks" (GF31).

Nowadays, the punishments do not typically involve physical torture - Dumbledore will not knowingly allow a student to be manhandled with impunity (OP27) - but nevertheless they can be extremely unpleasant. Filch, for example, was ready to lock Harry and Ron in the dungeons on their very first day when he caught them trying to open the door into the forbidden third floor corridor and wouldn't believe that they were lost (PS8). Teachers are given the freedom to choose the type of punishment they mete out, and Snape makes good use of this power to make life miserable for miscreants. Professor Moody overstepped this power, however, when he Transfigured Malfoy into a ferret and bounced him around the Entrance Hall (GF13). Umbridge far overstepped her power as a teacher through her standing as 'Hogwarts High Inquisitor', but left Hogwarts at the end of the 1995-96 [Y15 - Y16] school year (OP12ff).

Punishments vary according to the nature of the crime. Some infractions result in points being deducted from the offender's House. For other more serious offenses, detentions are handed out. Teachers may assign detention tasks as they wish and some detentions have been actually dangerous. If a student refuses to accept the detention, they can be expelled. Large hourglasses stand in the Entrance Hall, showing the number of House Points each House has accumulated (PS15).

detentions:

• search the Forbidden Forest with Hagrid in the dead of night (PS15)
  who: Harry, Hermione, Neville, Draco
  why: wandering around the castle in the middle of the night
  issued by: McGonagall
  points taken: 20 from Slytherin, 150 from Gryffindor
  result: school-wide bad feeling toward the three Gryffindors involved for improving Slytherin's chances at the Cup; introducing Harry to the Forbidden Forest, the centaurs in general, and Firenze in particular; Harry learned the properties of unicorn blood

• polish the silver in the trophy room without magic (CS7)
  who: Ron
  why: coming to Hogwarts in a flying Ford Anglia
  issued by: McGonagall
  points taken: none (school wasn't technically in session yet)
  result: Ron learned who Tom Riddle had been, having had a slug attack over his Special Award

• help Lockhart answer fan mail (CS7)
  who: Harry
  why: coming to Hogwarts in a flying Ford Anglia
  issued by: McGonagall
  points taken: none (school wasn't technically in session yet)
  result: Harry was out of his dormitory late, and heard the basilisk for the first time
  
  

• clean out the bedpans in the hospital wing without magic (PA9)
  who: Ron
  why: criticizing the way Snape taught when substituting for Lupin
  issued by: Snape
  points taken: none, technically, but he'd already taken 20 points over the course of the lesson up till then
  result: Ron learned that Lupin didn't spend his sick leave in the hospital wing
  
  

• unnamed detention (PA13)
  who: Marcus Flint, Malfoy, Crabbe, and Goyle
  why: pretending to be Dementors to make Gryffindor lose a match
  issued by: McGonagall
  points taken: 50 from Slytherin
  result: they didn't try that again in a hurry

• unnamed detention, together with loss of Hogsmeade privileges and denial of access to the Common Room passwords (PA14)
  who: Neville
  why: losing a list of the passwords to the Gryffindor common room, a list which Sirius Black obtained and used
  issued by: McGonagall
  points taken: none
  result: Harry had to dodge Neville during the next Hogsmeade weekend in order to sneak out himself

• disembowel a barrel full of horned toads (GF14)
  who: Neville
  why: melting his sixth cauldron in Potions
  issued by: Snape
  points taken: none
  result: Hermione helped Neville afterward by teaching him a Scouring Charm; he later asked her to the Yule Ball, but she already had a date

• pickle rats' brains in the dungeons (GF18)
  who: Harry, Ron
  why: yelling at Snape
  issued by: Snape
  points taken: 50 points from Gryffindor
  result: Harry had hoped to settle their quarrel during their joint detention, but a Daily Prophet article that same day poisoned the atmosphere

• writing 'I must not tell lies' with Umbridge's detention quill every night for the remainder of the week (OP12, OP13)
  who: Harry
  why: spoke the truth about Voldemort's return and called Umbridge a liar in front of the entire class
  issued by: Umbridge
  points taken: none, technically; she'd already taken 10
  result: Harry missed Gryffindor's Keeper tryouts that Friday

• writing 'I must not tell lies' with Umbridge's detention quill every night for the remainder of the week (OP15)
  who: Harry
  why: talking back to Umbridge about Quirrell
  issued by: Umbridge
  points taken: none, technically; she'd already taken 5, and McGonagall, hearing about the incident, took another 5
  result: Harry learned about murtlap from Hermione, although his right hand was still permanently scarred; Hermione was inspired to suggest what became the D.A.

• writing lines (ordinary) (OP19)
  who: Crabbe
  why: hitting Harry in the back with a Bludger after the whistle had blown to end the match
  issued by: Hooch (?)
  points taken: none specified
  result: taught the Slytherins that the system was a joke and the Gryffindors that it was unjust

• a week's worth of detention, unspecified - overruled by Umbridge, who changed it to a ban from Quidditch (OP19)
  who: George, Harry; Umbridge included Fred
  why: physically attacking Malfoy two on one after he insulted the Weasleys' parents and Harry's mother
  issued by: Umbridge, who overruled McGonagall
  points taken: none specified
  result: Ginny took over as Seeker, the twins were no longer motivated to stay in school, Ron under pressure as Keeper

• lines with Umbridge's detention quill (OP25)
  who: Lee Jordan
  why: cheeked Umbridge about Educational Decree 26
  issued by: Umbridge
  points taken: none specified
  result: Harry recommended murtlap to Lee, who recommended it to the twins, who used it to fix their Fever Fudge prototype

• writing 'I must not tell lies' with Umbridge's detention quill every night for the remainder of the week, loss of Hogsmeade privileges (OP26)
  who: Harry
  why: The Quibbler interview
  issued by: Umbridge
  points taken: 50 from Gryffindor
  result: none from the punishment as such

• whipping - but not accepted by offenders (OP29)
  who: Fred and George
  why: turning a corridor into a swamp
  issued by: Umbridge
  points taken: none mentioned
  result: the twins cast a Summoning Charm for their Cleansweeps and left Hogwarts in a blaze of glory

• sorting out rotten Flobberworms from good ones for use as Potion ingredients, without protective gloves (HBP9, HBP11)
  who: Harry
  why: cheek ("There's no need to call me 'sir', Professor.")
  issued by: Snape
  points taken: none mentioned
  result:

• unnamed detention on day of Hogsmeade visit (HBP12)
  who: Draco
  why: failing to turn in his Transfiguration homework twice in a row
  issued by: McGonagall
  points taken: none mentioned
  result: Draco had an apparently cast-iron alibi for planting the opal necklace on Katie Bell

• unnamed detention (HBP17)
  who: Crabbe and Goyle
  why: for slacking in Defense Against the Dark Arts
  issued by: Snape
  points taken: none mentioned
  result: Draco complains that he wouldn't be wandering around alone if Snape hadn't put Crabbe and Goyle in detention, Snape claims that they need to do better in DADA classes if they are going to pass their O.W.L.s this time around, and it is important for them to "act" as though DADA is important

• lines (ordinary): 'I am a wizard, not a baboon brandishing a stick.' (HBP17)
  who: Seamus Finnigan
  why: not concentrating in Charms, to the point that he produced a hoselike jet of water rather than a fountain from his wand, knocking Professor Flitwick flat on his face in the process
  issued by: Flitwick
  points taken: none mentioned
  result:

• clearing out Filch's old files recording punishments handed out - recopying any damaged records and filing them alphabetically without using magic - every Saturday until the end of term (HBP24)
  who: Harry
  why: cast Sectumsempra on Draco during an impromptu duel, then lied when questioned about where he learned the spell
  issued by: Snape
  points taken: none mentioned
  result: Harry missed Gryffindor's final match of the season, then kissed Ginny for the first time in the after-match celebration. Also, Snape had arranged matters so that Harry began with the records of the Marauders' school years, which meant that Harry was constantly encountering mentions of them during his own detention.

• unnamed double detention (HBP24)
  who: James Potter and Sirius Black
  why: cast an unnamed illegal hex upon Bertram Aubrey to swell his head to twice normal size
  issued by: not named
  points taken: none mentioned
  result: Harry had to read the record of this detention and check it for damage as part of the contents of boxes 1012 - 1056 of Filch's records during his own detention with Snape in his sixth year.