According to the Special Theory of Relativity, at speeds approaching the speed of light, time dilation comes into effect. The consequences of this are that if your space ship leaves the Earth and travels at 90% the speed of light, the clock on your ship will tick half as fast relative to my clock back on the Earth. If your space journey takes one month according to your clock, two months will have passed for me according to my clock. You will have traveled one month into the future at your arrival back on Earth.
Now let's say it's 2050 and some billionaire entrepreneur, some future Richard Branson, invents a propulsive system and a space ship that is able to achieve near light-speed. He advertises Flights Into The Future, Tickets Only Ten Million Dollars. You buy your ticket, enter the ship and it accelerates to 90+% the speed of light for say six months ship time. Due to time dilation, during your voyage two hundred years will have elapsed on Earth. When your ship returns it's 2250. What an experience you will have experiencing future Earth!
The only drawback is it's a one-way voyage in time. You can never return to the world you knew when you left. What would be the consequences for you and for the future society trying to accomidate your fellow time-travelers? Would you have the courage to make this journey into an unknown future?