John Titor claimed he was a time traveler from the year 2036, who came back to the 1970's and again in 2000-2001. His first stop was to get a old IBM computer and bring it back to the future with him. He then stopped in the year 2000, and stayed till 2001, which in that time he made some prophecies on the internet on different chat lines, and explained alot of details of his time machine and why he was here. Some of them still exist today and you can read yourself just google "John Titor Chat".
Most of his prophecies were wrong but he said his timeline was different then ours, and that somethings wouldn't be the same anyway. Also, Y2K happened for his world, which caused a civil war in his time. Some people speculate that he stopped Y2K for us and thats why the war never happened for our timeline. A couple of his prophecies did come true however eg: He said that a building will be missing out of the NY skyline,(a couple of months before 911) He also talked about cern and there studies with blackholes before they even knew. He also stated that the research they did there contributed to time travel, thats yet to be seen of course.
The knowledge he had of the IBM computer he needed was uncanny, details and things it did that only a few people that built it knew about, which makes it even more mysterious. Crackpot or not its a very interesting story and i enjoyed researching it. Heres a good website for more on john titor. http://www.johntitor.com/