Video: Expelliarmus. Avada Kedavra. Expecto Patronum. Crucio. If you're a Harry Potter fan (and the entire world is), you ought to know what those famous spells do. If you don't, watch this awesome supercut from Davide Rapp that alphabetises all the spells used in the Harry Potter movies and then shows you the scenes in which they're used.
It's a lot of fun. Possibly more fun than reading Harry Potter and the Cursed Child.