That is pretty cool Bob.
Most of mine seem to be travel related:
I ran into a girl a knew from KC in the Narita airport in Tokyo. I saw her coming a long way away, so when she noticed me I just said "hey what's up", very casually. Her jaw dropped to the floor. That was fun.
My dad just visited his estranged brother, whom he hadn't seen in 25 years. The only reason this happened his his brother's best friend happened to be in Positano, Italy (where our family is from) at the same time me and my Dad were visting.
Here's the full story if anyone's interested.
A good friend of mine in LA I know through two different unrelated friends from Kansas City. So if either connection wasn't there, I would still know her through the other one.
I can name at least 50 people scattered around the country, including some of my good friends in LA, who all know each other solely due to a connection made between me and another group while I was in SF. The lynchpin of this conncection is a quiet, often drunk, always broke waiter I used to work with, that no one even knows that happened to anymore. For some reason it always freaks me out to think of that.