Have had a few encounters, but two stand out. In the 1970's I worked in Oklahoma City. Union Oil had a drafting office on the same floor, and one of the guys that worked there was good friends with our secretary, and would come over and camp in our office on his coffee breaks. He and his wife had six kids in a "yours, mine and ours" combo--two hers from a previous marriage, two his, and two theirs. The two that were theirs were in high school then, and he was always bragging on them. One of them played the guitar and sang, and one summer he brought him up to the office a couple of times, and we sat in their drafting room and listened to him. I thought he was ok, but nothing special. Flash forward a few years, and I'm working in Denver, driving down I-25 and listening to the local country station. They played a song and I hadn't heard, and when it was over the DJ said "And that's the new song by Garth Brooks." I almost ran off the road. That evening I called a friend who had been a part of those "concerts", and who still lived in OKC. I told her about hearing the song and said, "That's got to be Troy's son, right?" She confirmed it. She and my secretary were still in touch with Garth's family, and that year or the next I made major points with my niece by using those connections to get her an autographed Garth t-shirt for Christmas.
The other one only sort of counts because I can't remember the guy's name, and it was more history than a celebrity encounter. We were in the Houston area for a few years between Okla. City and Denver, and I was working at a small bank west of Houston. There were several Cuban expats there, most of them driving trucks. One of them came into our bank and applied for a truck loan. On his application, it said he came to the U.S. in 1962. I asked him about his immigration, and he said that was when he was released from the Isle of Pines prison, and the Cubans let him leave the country. I said something to the effect that the Isle of Pines must have been tough, and he just looked at me and said "Tough and a half!" I asked him what got him imprisoned, and he said he was captured at the Bay of Pigs invasion, and was commander of the Cuban rebels invading force. Our bank auditor was there at the time, and he was a real history buff. After the guy left, I told him the story (both of us fairly skeptical). There was a really good book about the invasion out at the time, and it so happened that the auditor was reading it then. He brought it in the next day, and sure enough there was the guy's picture. He (the Cuban, not the auditor) brought by a copy of a Miami paper later, with the news story of him being coming to the states and being greeted by JFK (maybe in an Orange Bowl rally, if I remember correctly). Several years later, I read that he had committed suicide.