Geriatric division: I was pretty good friends with a guy in my platoon in Vietnam, but didn't make any attempt to stay in touch after we came home in 1968. In 1973 or '74, I was riding a cruiser on the hard sand on the beach in Santa Monica and met him coming the other direction. Double-take, how you doing, nice to see you.
Cut to 1985, riding a mountain bike in the desert near Tucson. It was getting dark, so I cut through a subdivision trying to get back to my motel. As I fumbled with the key card to get my bike into the room, the same guy came down the hall pushing his own bike.
Jump ahead 25 years. I'm picking up my number for a group ride in Indianapolis, and as I waited, my eye fell on a tag with his name. Could it be? I looked around and didn't see anybody who looked like him, but he was 30-something last time I saw him and he'd be close to 60. I hung around for awhile, and in a few minutes he showed up--with a son older than we were when we met.