On December 7th, I published, Got Gold?:
"Accordingly, today I'm adding some calls in the XAU index (February 130's), based on the same bull market leverage theory espoused in this prior blog."
At that time, Gold was at $505oz, today, it's up 10% from there to about $555oz. The $XAU was at 122; today it's at 141. Those February 130 calls went from $2.10 to today's $13.40 X $13.80.
You can afford to be wrong a few times on these plays, and then be right once to make out very well. Bull markets are like that.