I've known for some time now of the effects a black hole can have in time travel. A very fundamental role in Physics is the more massive an object, the slower time goes. So, if you were able to travel to the center of the galaxy to the Super Massive Black Hole and start flying your spaceship in a circle around it the time difference would be something like 50 Earth years go by for every 10 or yours. However, in Dr. Ronald L. Mallett's book, Time Traveler, He speaks of his continuing journey to find a way to travel back in time.
One way, that he has found is that because of gravitational waves given out by black holes time loops are created. (To know more about the affects of a time look watch the movie with Christopher Reed, Bid Time Return). So in theory, we could travel to any rapidly spinning black hole, get caught in this time loop, go back in time, and then fly out. Hmmmm.