It kinda looks like a Cryptic Crossword clue. My guesses:
1) One night a week?
2) Silent Night
Otherwise, I'm stumped.
_________________
It is easy to go down into Hell;
Night and day, the gates of dark Death stand wide;
But to climb back again, to retrace one's steps to the upper air –
There's the rub, the task.
– Virgil, The Aeneid (Book VI)