Bethesda announced that Fallout 4 is having a free trial period this weekend on Xbox One and PC. Xbox One players require an Xbox Live Gold subscription to download the trial.
Here's when the trial be available on Xbox One and PC:
Start: May 25th, 2017 at 12:01 a.m. PDT (3:01 a.m. EDT)
End: May 28th, 2017 at 11:59 p.m. PDT (2:59 a.m. EDT)
PC via Steam
Start: May 25th, 2017 at 10:00 a.m. PDT (1:00 p.m. EDT)
End: May 28th, 2017 at 1:00 p.m. PDT (4:00 p.m. EDT)
In addition, Fallout 4 and its Season Pass will be discounted throughout the weekend on Xbox One, PC and PS4.