Several times in the past during my philosogossips with my friends I used to mention that if not for British's ruling, traveling to India would be like time-travel into the past. Recently I was watching an episode on a popular-flavored time travel episode on History channel. The episode makes it reasonably clear that although science does not prevent time travel (something like we can not prove P not equal to NP), it's the amount of speed that's needed. For now nothing less than needing (exponential) energy seems possible for general purpose time travel although there seems to be a case of one person being 1/50th of a second in future because of his space travel.
And a few days ago while biking it just occurred to me time travel to the future might be thought of as already happening in our daily thoughts. See for time travel we need speeds close to the speed of light. Now, its easy to follow the thought experiment.
1) Thoughts can take "you" (make you experience) instantly across vast distances so lets say they have high speeds for experiential purposes.
2) Some people whose thoughts travel fast can "see the future".
3) They can "come back" and to let everyone see that future have to invest energy. In general they would require exponential amount, but thanks to collaborative efforts we "can pool" that required energy.
4) The time scale for everyone else to experience that future depends on how fast the pooling happens.
5) Coincidentally I can cite the example of Dr. King's vision for civil rights as the news on rallies in DC is running in the background on CNN.
So in a way if some one is aggressive enough to envision a future, clever enough to pool the resources by smartly tapping the collaborative instinct available abundantly in life, we can travel to the future. For e.g. if there wasn't such effort our grand-parental generation would not have seen the "future of such high technological advances". Whether time travel is good and wise (for survival) is a whole another topic! So far advances in civilization seem to be strong in saving lives, whether it's taking us on a sub-optimal time travel path instead of the "regular speed" time travel to the future, I don't know if it's possible to answer.
BTW everyone is forced to time travel in the forward direction, I am talking about the speed which distinguishes future from the present. Past I don't know much, although some cyclic experiences or deja vu's seem to be occurring sporadically :)