Today, in reading some data, I processed 36,916 potential dates. Two of those 36,916 failed to validate. I wasn't terribly concerned as these dates come from client-supplied data and this data is often, um, surprising. However, when I inspected the raw data, it turns out that those dates were January 1st, 2011 and January 1st, 2007. I had a bug in software I wrote about a month ago, but it turns out that this bug is actually 30 years old.