I'm going to post here at some point in the next week, when you don't expect it.
A paradox, because if I waited 6 days, it would be obvious that I'd post on the seventh, and therefore if I waited 5 days, I would have to do it on the sixth, and so on. However, because of that, you won't expect me to post on any of those days, and because of that, you will expect me to, etc.