Spells
Spell used to unlock doors and other locked objects
Alohomora
The first Horcrux to be destroyed
Tom Riddle's Diary, by way of Basilisk Fang
James Potter's position in Quidditch
Seeker
Edward Remus "Teddy" Lupin
The Three Unforgivable Curses
Avada Kedavra, Crucio, Imperio
The first to die during the Triwizard Tournament
Cedric Diggory, at the graveyard, killed by Peter Pettigrew
The framed and the true culprit for a crime repeated during Harry's 2nd Year
Rubeus Hagrid framed for Tom Riddle's opening of the Chamber of Secrets.
Be brave Professor, brave like my mother. Otherwise,you disgrace her.
Alastor "Mad-Eye" Moody
Finish the incantation: Finito...
Incantatum
The reason Harry's broom was acting up during his a Quidditch match against Slytherin
Professor Quirrell was using a jinx on his broom.
The reason behind Snape's disdain for Harry Potter
James and friends' bullying of him during their school years.
Finish the quote: Kill the...!
Spare!
Hagrid's pet spider
Aragog
The combat spell Harry learned from and went on to cast against a Hogwarts Professor
Sectum Sempra
The pact made to save Draco Malfoy's soul
Snape made an Unbreakable Vow to Narcissa Malfoy that, should Draco Malfoy fail to do so, Snape will kill Dumbledore
The connection between the Marauders
They were all Animagi
Harry's answer to this: So tell me, Harry. Here you sit, a mere boy of 12...
I'm 14.
Marauder nicknames and their corresponding real names
Moony, Padfoot, Wormtail & Prongs - Remus Lupin, Sirius Black, Peter Pettigrew, James Potter
The spell used by two Death Eaters that allows them to read minds
Legilimens
The form of torture one of the trio underwent in their pursuit of the Horcruxes
Bellatrix using Crucio on Hermione; Branding Hermione as a mudblood.
The reason for the estrangement between Albus Dumbledore and his younger brother
Ariana Dumbledore's death in 'her brother's pursuit of power'.
The origin of Tom Marvolo Riddle's name
Tom Riddle from his father(A single bonus point for the origin of his middle name).