I'm actually related to myself...
I was adopted at 5 days old. My parents moved from the city I was born when I was a baby and I grew up in another country. My birth mother and adoptive mother are the same nationality. A few years ago, my adoptive mother had asked me to do some research on her family tree...turns out my adoptive mother's great great great grandfather had a sister, and this sister is my birth mothers great great aunt.
Also, my birth mother married a man 10 years after I'd been adopted (not my birth father). Her husband and my adoptive Dad went to school together. My dad wasn't from that area but he'd gone to live there with his mother as WW2 broke out a few months after he was born. Dad returned to London with his mum after war had ended so really if it hadn't been for the war, they wouldn't have ended up going to school together.
Lastly, my birth mother has worked in retail in the city I was born at the university. Two of my friends went to uni here and back in 1997, I went up to visit them one weekend and we went into the universality bookshop, bought some books and then left. It was the shop where my birth mother works and she'd been there that day.
I should add that my adoption wasn't an open adoption, my birth mother only found me 6 years ago (when I was 32) so our paths really shouldn't have crossed at all seeing as I'd moved away from there as a small baby. She was very young when she had me and it wasn't acceptable to be a single young mum in the late 70s but we have a fabulous relationship now and we're still spooked by the coincidences (as is my adoptive mother!).