The launch window is tomorrow, 6:10 Eastern / 3:10 Pacific.
UPDATE: Launch was scrubbed on Sunday due to an issue with an avionics transponder. They're going to set up for tomorrow but we'll see. If it's hardware though it's unlikely to go.
They land on barges around 250 miles out to sea. They're autonomous vehicles that use multi-directional engines to hold their position.
In a tribute to the recently-deceased sci-fi author Iain M. Banks, Elon Musk decided to name the barges after spaceships in his Culture series of novels. Those ships tended to have somewhat quirky names, chosen by the AI minds that ran them. The two SpaceX ships are now "Just Read the Instructions" (east coast) and "Of Course I Still Love You" (west coast).
By a strange coincidence, just this past week I finished listening to "Use of Weapons," the third book in the Culture series on Audible. Pretty good narrator. Strange book, as they are in that series. Of the ones I've read/heard, "Player of Games" is my favorite. It'd be among my all-time top novel picks.
Last time they tried this, SpaceX got close. They reached the ship but the booster crashed onto the ship's deck as it ran out of maneuvering fuel. (Elon commented that they'd added 50% more maneuvering hydraulics, so if it crashes "At least it should explode for a different reason."
Good luck tomorrow, SpaceX!