On BBC America, a 50th birthday party for Doctor Who: Still charming, but always alien

In television's vast universe, there is perhaps no acquired taste that is more difficult to acquire than the taste for "Doctor Who," BBC's long-running sci-fi series about an alien dandy who navigates the time-space continuum in a phone-booth-style British police box. It's been on (and off, and then on again) for five decades, but despite its increased popularity, "Doctor Who" remains steadfastly niche.