This is going to be a partial answer, but probably as good as you are going to get.
There are certainly congregations that practice prophecy in their open worship services. Many Pentecostals do. There is at least the possibility that a member of the congregation will prophecy aloud something that "discloses the secrets of the heart" of an outsider present.
Whether this happens often is an excellent question. Churches do not plan for particular kinds of prophecy. A true prophetic message is always initiated by God. A church cannot say "let us now prophecy things that will disclose the secrets of someone's heart" without running the risk of attempting to control God and hence blasphemy. A much more appropriate attitude is to be ready for whatever prophetic message God wishes to send.
It is also not guaranteed that anyone affected in such a way will choose to make their experience public. It may remain private to them, or private to them and the church.
There are examples of such things occurring. You might start by reading the books of John Wimber. This article by John Piper, identified by GratefulDisciple, also gives some specific examples.