I bet you read the Harry Potter books, didn't you? And saw all the movies? Probably a few times each.
It's very different when you're cramming for a quiz on them. A bit like college, actually. Every detail suddenly seems like something you should remember.
Do you remember the four types of dragons in the Tri-Wizard Tournament in Goblet of Fire? Do you remember which champion got which dragon?
What was the name of the witch Hermione impersonated to infiltrate the Ministry of Magic in Deathly Hallows? What was her job?
What's Ron's middle name?
What school did Dudley attend? What school would Harry have gone to if he hadn't gone to Hogwarts? And what school did the Dursleys tell people he went to?
What is a budgerigar, anyway?
As my friend just said on IM ... I feel like Ron Weasley before a History of Magic test.
If you have any random Harry Potter facts you'd like to share, please, lay them on me.