BoingBoing carries a video from Jamie D. Grant, a magician, which purports to show a time traveller. I don't usually like to put spoilers in my blog, and the video is only a couple of minutes long. You can see it here....
OK... a guy who has a modern look appears in an old photograph. It's a bit like the video of the old lady apparently using a mobile phone... you see what you think you see only with the perspective of your time and place. I've embedded this version only because I think it is the original, but the guy does witter on a bit - the actual film starts around two minutes 39 seconds.
The Hakan Nordkvist case is more intriguing on first viewing. It's a hoax... how can it not be? Apparently a stupid retirement company thought a viral hoax might encourage young people to plan for their retirement. Once again, the "proof" isn't proof at all.
The most persuasive argument against time travel is simply that we do not have people from the 31st century arriving as tourists to screw up the future in some mind-bendingly confusing way. I'm assuming anyone capable of developing a time-travelling machine will be a geek who's watched enough Star Trek to know it never turns out well anyway.