Slime Central, or Goo Fort, was Sips and Sjin's base on the MoonQuest server. As the name suggests, Slime Central was on a tamed slime island. It featured a quarry, a cobblestone house, and a large wooden platform surrounding the outskirts of the island. It was Sipsco Space Program's primary headquarters.
However, in episode 30, Sips was mysteriously replaced by Zips, a clone of Sips. Zips rigged the whole island with TNT, and Slime Central was destroyed.