But if you really want to get discussions moving, there's an excellent discussion "hook" technique that I learned while hiking the Inca Trail to Machu Picchu. It's virtually guaranteed to spark interest.

Okay, you've sparked my interest. Is the "hook" telling folks about an excellent (fill in the blank) that you learned while hiking the Inca Trail to Machu Picchu?

The "hook" is starting an interesting story, relevant to the listener, that you don't finish telling. You return to your original story in the conversation, or go off on another tangent, "forgetting" about the hook story.

Thus getting them to ask, "so what happened on the Inca Trail"?

Though using an experience from your own life is bound to be more realistic and effective.

Charlie and I are standing at the top of a hill overlooking Machu Picchu. The fourth day of the hike, and we've hiked an hour that morning to get to the top, and are awed by the view. "Breathtaking," I mutter. "Yeah," he replies, and begins to point at the ruins. "But soon there'll be ... " He trails off for a moment, and starts walking toward the site. I start after him, but he won't finish the sentence and changes the subject.

An hour later, two buses of tourists arrive and the site is swarmed. "Too many people", he says, pointing again, finally finishing his sentence.

I had to wait for it and ask for it, and when I got it, there was a much bigger impact.