When John Titor first showed up on IRC chat in October of 2000, he was enjoying a neat kind of double billing – as his 38-year-old self sat downstairs in the kitchen, typing away, a two-year-old version of himself lay sound asleep upstairs in bed. The elder Titor had been sent back in time by the U.S. Army, which needed him to fetch some legacy computer hardware from the 1970’s, and he had a sort of layover in the year 2000. So like anyone with time to kill, he went online.
Titor arrived in Florida in a 2036 model Corvette (later sold off) outfitted with a 500 pound military-grade time travel device that he photographed and posted online, complete with manual. The reason for his visit was utilitarian – he had been sent back to the 1970’s to fetch a model IBM 5100 computer, “because Unix has problems in 2038”, and the 5100 had an undocumented feature that made it highly desirable to programmers working on the Unix bug. Apparently the Army of 2036 knew enough to build a time machine, but wasn’t able to fix a word-size error in a legacy operating system.
That bit actually made the whole story sound plausible to me.