Anyone who's read the Harry Potter books or seen the movies knows Hermione Granger. She's the muggle-born witch who is easily the smartest student in Hogwarts School of Witchcraft and Wizardry. Hermione is studious and quick-witted, and as part of the heroic triad in the series, she bears her fair share of battling evil.
But if your only experience of Harry Potter is through the films, you won't know anything about Hermione's revolutionary side, or her use of knitting to battle social injustice. Unfortunately, that storyline was eliminated from the movies.
To give some background, Dobby the house-elf is introduced in Book 2 (Harry Potter and the Chamber of Secrets). House-elves are essentially slaves – they will serve one family for a long part of their life, and they feel that this is right and proper, that this is what they were created to do. House-elves can be freed; giving a house-elf clothes frees it from its situation. Most house-elves, however, do not want to be freed, and resist the suggestion most strongly.
In Book 4 (Harry Potter and the Goblet of Fire), we are informed that hundreds of house-elves live at Hogwarts, cooking for feasts, cleaning, and doing other chores. Hermione is outraged that Hogwarts would condone slavery, and she creates an organization: the Society for the Promotion of Elfish Welfare (S.P.E.W.), which is met with overall indifference from her fellow students.
In Book 5 (Harry Potter and the Order of the Phoenix), Hermione takes it upon herself to free as many house-elves as possible. In addition to keeping up with her studies, acting as a Gryffindor prefect, and forming "Dumbledore's Army" to fight evil, Hermione spends her free time knitting hats and socks. She leaves these lying around Gryffindor Tower, hoping to free some unsuspecting elf who picks them up while cleaning the common room, and so grant them freedom. The house-elves don't appreciate this gesture; on the contrary, they take it as an insult and refuse to clean the common room, with the exception of Dobby.
While Hermione's fight to free house-elves is to no avail during her Hogwarts years, J.K. Rowling does write that as an adult, Hermione goes to work for the Department for the Regulation and Control of Magical Creatures and works successfully to improve the lives of house-elves.
And so, I present to you Hermione Granger: genius, loyal friend, freedom-fighter ... knitter.