Cool post. My thoughts:

• Computer skills, to the unfamiliarized. I've written a script to do something and others have been amazed that I can do some task so quickly.
• Complex Excel functions. People definitely have a "magic awe" response when Excel does something apparently amazing before their eyes and the formula doing it is longer than the cell text entry box.
• Knowledge of how to use a terminal and command line tools.
• The ability to empathize and "think in the shoes of another." I once asked someone if they believed in the flood and Noah's Ark. They were silent for a bit and then I asked, "Are you wondering what the Catholic Church's stance on it is?" They were somewhat blown away that I knew that's what they were wondering. This is a silly example, but it just comes from knowing that if a) I knew I needed to believe what the Catholic Church teaches, and b) I didn't know what they taught about the flood, and c) someone asked me what I thought about the flood... I'd be wondering what I was supposed to think about it.
• Any repetition learned task. Seriously, anything that you're well-above average at that is either entertaining or useful can mesmerize. Guitar, dancing, stacking cups, some kind of tricks (card, zippo, magic, etc.)

Anyway, there's some of mine. I think the unifying key is that if someone can't figure it out and it's impressive or useful, they'll be slightly in awe, at least if they actually want that ability as well.

I add this last part, as I have been in awe of some skill X, but been pretty indifferent about Y because I didn't really care about Y.

Replace jelly bean predictions with predictions about some text-based mmorpg based on exactly the same arithmetic. Do you think anyone would have cared?

They probably saw "magic" because a) they wanted delicious jelly beans and b) they wanted the thrill that comes along with winning/impressing others. Had you shown them how to win some mmorpg by averaging numbers, they probably would have said "neat" and walked away.