So I found this on Tumblr, where they have various 30-day challenges that go around. This is the 30 Day Harry Potter challenge. Basically you start with answering Question 1, then come back each day and answer the next one until you're done.
Have fun!

Day 1: Your fave book?

Day 2: Your fave movie?

Day 3: Is there any of the films adaptations that have made you angry because they’ve ignored important parts of the book?

Day 4: Least fave female character and why?

Day 5: Fave male character and why?

Day 6: What house would you want to be in?

Day 7: Fave female character and why?

Day 8: What do you think would be your fave lesson?

Day 9: Least fave male character?

Day 10: Horcruxes or Hallows?

Day 11: What character would you say you are most like?

Day 12: Fave ship?

Day 13: Least fave movie?

Day 14: Team Voldermort or Team Harry?

Day 15: Who would be your best friends at Hogwarts?(three only)
Day 16: Fave professor?

Day 17: Are you excited about The Deathly Hallows movie or scared it won’t do the book justice?

Day 18: Least fave book?

Day 19: Do you prefer the books or films?

Day 20: If you had to meet one member of the cast, who would it be?

Day 21: Out of all the characters that died, if you could bring one back, who would it be?

Day 22: Harry Potter or Twilight?

Day 23: Any part of the books/movies that makes you cry?

Day 24: Any particular scene you wished would have been put in the movie but it wasn’t?

Day 25: Nineteen years later. Are you happy how it turned out, or do you wish something was different? )ie Neville married Luna)

Day 26: If you could be able to work one spell without a wand what would it be?

Day 27: Would you rather own The Invisibility Cloak, The Resurrection Stone or The Elder Wand?

Day 28: Do you listen to Wizard Rock, what do you think about it?

Day 29: Did you enjoy A Very Potter Musical?

Day 30: What effect has Harry Potter made on your life and how much does it mean to you?