What are the chances, van den Berg?

I have a really common surname. Sure, I spell it "Vandenberg" (because I was born in Zimbabwe and grew up in Europe) but back here in the homeland, I have to face the fact that my name is actually van den Berg, and is about as interesting as "Smith" is in Britain. There are so many of us here, it never, ever even occurs to me to wonder if any of them are related to me. Which makes today's bizarre meeting that much more delicious. There I was, MC-ing for an educational workshop event thing, and hey! There were a couple of teachers (who were also an actual couple) with the same surname. Ha ha! A little laugh, a friendly joke about how many of us there are, and then something - something this nice man said made me sit up. "Sorry, what?" I could have sworn he just told me a special family story that is MY special family story. That one about my great-great-uncle who owned the farm where Winston Churchill was kept prisoner (in a POW camp) during the Boer War. "Say what now? Excuse me? Did you say 'Langkloof'?" For a surreal moment, I doubted that OUR family story was true. Had we picked this up somewhere, embellishing the family name with something historically interesting? But nah, that can't be it, because I KNOW that was my grandfather's uncle.... which (dawning realisation) means that... you are - oh my word - YOUR grandfather and my grandfather were cousins. Or something. Whatever. WE ARE RELATED?? Holy Smoke! I suppose I shouldn't be all that surprised. After all, we've been dining out for years on the fact that my children's dad's great-uncle arrested Hitler, which means our kids are related to people who imprisoned both Hitler and Churchill. That's pretty marvellously weird, by itself. And yeah - their dad's side is definitely looking better in that story.