This year’s Twilight Zone marathon continues all day and night, and goes into tomorrow – so any time you like, you can into the Zone merely by tuning to Syfy. But this year, today, I highlight in particular the 8 p.m. ET showing of “The Invaders,” the episode of The Twilight Zone I singled out for praise, and interpretation, as my contribution to Mark Dawidziak’s Everything I Need to Know I Learned in The Twilight Zone – the perfect companion book, by the way,