Ban him/her and move on.
Shutting down at a certain time would be problematic BC we're on different time zones.
My three cents (only two of mine but one automatically gets added because they're from me and I'm awesome):
Shutting the forum down every "night" and blocking casual views for that matter is like fishing with dynamite.
When you only wanted one fish.
And it might not even be down there.
In fact it's probably not down there.
But hey, it's just fish right? Fuck 'em. Light that candle and toss 'er overboard.