Let's see, I asked a stupid question on Tuesday, overanalyzed the act of writing on Wednesday...what else should I do this week? Oh, I know! Let's have a pointless Doctor Who post! That'll turn off about two-thirds of the readers. So here's the question I've been pondering for a while: What episode of the modern series would you use to introduce a newbie to the show? Said newbie could be an adult or your own kid, but definitely American, so he or she hasn't absorbed anything Who-ish from the broader culture -- in short, they've never heard of the show. You don't get much time for pre-show exposition, either; just "That's the Doctor; he's an alien time-traveler. The girl is his friend; she's human."
The obvious candidate is "Rose," since that's where the modern series started, but...well, it's not a very good episode, is it? And I think it does rely a bit too much on the viewer knowing what's going on in advance...or at least, more than Rose does. Any Dalek or Cybermen episodes are out too, for the same reason, as well as "School Reunion." Also the final three episodes of Season 3, and I'll just leave it at that, in case anybody hasn't seen them yet.
Still, any season-opening episode should have the right "starting out" feel, right? Well, except that "New Earth" is awful, and relies on the viewer remembering both Cassandra and the Face of Boe, so...not so much. "Smith and Jones" feels like a much better candidate to me, as it really does start from scratch, from Martha's point of view. Plus, there's my personal bias that I prefer the Tenth Doctor and Martha to the Ninth and Rose, so I like that.
The Christmas specials are meant to be one-shots, so they should be more accessible, right? Well...the Doctor's barely in "Christmas Invasion," and there's all the Harriet Jones/Torchwood stuff, not to mention the confusion of regeneration, so...no. And "Runaway Bride" really isn't very good. I'm sure Donna will be much nicer when she comes back again later, but for audiences who've never heard of Catherine Tate, and don't find her automatically amusing, Donna is just completely annoying. And then there's the horrible spider effects. OK, so those two are out.
What about the really scary ones, by Stephen Moffat? Good choices, but as much as I love "Blink," the Doctor is hardly in it. "Empty Child" is a good choice, if I bend the rules and allow two-parters to count as one, but there is an awful lot of Jack in there, and "Everybody lives!" doesn't have as much punch if you don't know why that's unusual.
I think, depending on what you want to demonstrate, that "The End of the World" or "Unquiet Dead" are pretty good choices. You get either the sci-fi or the historical elements, depending on which one you choose, and it's all still new enough to Rose that the viewer can still latch on. Likewise, "Shakespeare Code" is pretty similar to "Unquiet Dead," but with The Tenth Doctor and Martha. I'll leave out "Gridlock" though, because, well, it's kind of dumb.
And then there's "Girl in the Fireplace." It's got Mickey, which is a bit of an added complication, but he does provide some new-viewer accessibility that Rose can't by that stage. It's both historical and sci-fi, which is good, and it's a darned good story on top of all of it. The only thing I'm not sure about, though, is whether a new viewer will feel the same impact in the Doctor's willingness to abandon everything -- the TARDIS, Rose, his whole way of life -- to save Reinette.
So I'd say "Girl in the Fireplace," followed by "Smith and Jones," and then either "End of the World" or "Unquiet Dead," your choice. All of this was prompted, by the way, by that in-flight showing of "Unquiet Dead" that I saw two weeks ago, which made me wonder if it was a good choice to show people who presumably had no context for it. Also, I have a six-year-old who hasn't seen the show yet. I've judged it too scary so far, although I know that if we lived in Britain, his friends would have been watching it for years now.
If you really want, for bonus points, you can discuss which classic episode is best to start with. I'll just take the easy way out and say "City of Death," without thinking about it too much.