The general consensus here seems to be that being 'slain in the spirit' is a scam, but let me tell you my story.  I attended the Methodist church with my grandmother when I was young, got married to a Catholic in a Luthern church that my family attended on Christmas and Easter only.  To say the least, I was about as far away as someone who believed in being slain in the spirt as the man in the moon.

Years later, I attended a Church of God service with a friend of mine.  They had a special guest, I don't remember his name, but he had a prision ministry, being an ex-prisioner himself.  At the end of his sermon, he made an altar call for those who wanted to be healed, blessed, etc.  He began laying on hands and people were dropping like flies.  I stood back and watched, scoffing to myself that this couldn't possibly be real.  I stood well back from the line of folks, but thought to myself, "I wonder if there really is anything to this?"

Then I said to myself, "If he calls me forward when he gets to this end, I'll go up there.  But not unless he calls me."  Well, the speaker moved to my end of the room, looked up and motioned for me to come forward.  He said something, laid his hand on my head and I fell like a rock!  I couldn't believe it - the true skeptic, felled with one touch.  It was as if my whole mind had emptied and my bones turned to jelly. 

It was not at all I what I was expecting, but it would be interesting to hear someone elses point of view.