Okay, this may be entirely fictional....

I'm sitting on a bus.  Across the way from me is a man in his early thirties, who has obviously seen better days - tattered shirt, tattered pants, and a faded AC/DC T-shirt.  He holds his head in his hands, blearily rubbing a prickly face with his palms. 

"When did it start going wrong, man?"  He asks, to no one in particular.

I am to help.  "September 18th, 1997."

He looks up, confused.  "What?"

"September 18th, 1997," I repeat.  "At around 4:43 p.m."

There is a long pause, before he speaks up.  "What happened?"

"Hm?"

"On September 18th, 1997?"

"What about it?" I ask, a bit confused.

"Well, what happened."

"When?"

"On September 18th, 1997."  He says, a little lost.

"Oh!  Right!" I say, nodding my head.  "I remember now.  The day everything went wrong!"

He nods.  "So, what happened?"

"Oh, everything went wrong then."

He is getting a little frustrated.  "I know... but how did it all go wrong?  Why did it all go wrong?"

I shake my head.  "You didn't ask how it all went wrong.  Or why it all went wrong.  I'm afraid I can't help you."

"What?"

"I specialize only in answering when.  I'm kind of a limited prophet."

"A what?"

"Hmm?" Is all I say.

"What's a limited prophet?" 

"I don't know," I answer, honestly.

"But you just said you were a limited prophet!  How can you not know what that means?"

"Well, I don't answer how...." I begin. 

He slams his head into the floor, and then runs off the bus screaming.  At exactly 2:33 PM, on June 4th. 

Totally knew it was going to happen, too. 

Just didn't know what "it" was until it happened.