Rule of Two?

Tonight it is, because I have only two things to say. A statement and a question:

1. The shower curtain scene, though overused, terrifies me every single time. I know "it" is never behind there, but I have to cover my eyes every time. I am going to successfully use a shower curtain scene someday, and "it" WILL be behind there.

2. When writing a spec of an existing series, how important is it that the series is currently on the air? What is the grace period for how long a show can be out of production before your spec is no longer acceptable?