I recently had "the Talk" with my kids.
You know, the one about time travel.
Lately, the discussion at our house has been all Harry Potter, all the time. I'm reading the books to Ariella (and Yaakov, who occasionally pops in for a listen), and then she's rereading in Hebrew, and then I let them watch the movie. So we are very heavy into practicing our wingardium leviosa and expelliarmus spells using random pencils we find around the house. And asking many, many questions.
Some are questions I have always wondered myself, like "Where do the professors live?" And some I never even thought of. Such as, "How did they choose the house ghosts?" Hmmm. No idea.
We just finished book 3, and by far the most difficult sugya we have dealt with to date is time travel. (Luckily, snogging doesn't happen until book 4).
If you recall, back in those heady days when you were reading Harry Potter for the first time, the trio listens from afar as the executioner kills Buckbeak (or so they think.) We keep reading, and we see that in fact Harry and Hermione went back in time, using Hermione's Time Turner, to save Buckbeak and Sirius. (I would have posted a "Spoiler Alert," but honestly, if you haven't ready Harry Potter by now, you're a Muggle with a capital "M.")
Ariella asks, "Okay, but who saved Buckbeak the first time?" ("See, but this is the first time! Even though it's later and it happened already!")
Yaakov wants to know, "So which ones are the real Harry and Hermione and which ones are the fake ones?" ("They're both real, 'cuz they went back in time and now can see themselves from three hours ago!")
Next up: A Wrinkle in Time and Back to the Future.
It's good to have the proper resources when explaining complex matters to your children.