Stephen Hawking's Time Machine Instructable
It's super easy - all you need is a Large Hadron Collider-style spaceship that travels 2,000 times faster than we've ever traveled before.
Stephen Hawking's Time Machine Instructable
dailymail.co.uk
Also, we can't travel into the past because of paradoxes - i.e., we would've known if we could travel into the past because it would've already happened in the future (duh). I guess we're all already traveling into the future, technically, but this would be a way to do it faster. (Via.)