'Hey Ben, how was your night with that girl?'
'She was adequately sausaged , mate! she was adequately sausaged indeed! *insert fist bump .. or high five ... or a similar celebratory action*
A phrase used when you want to give someone props for something that isn't even "pretty good", but isn't quite bad either. It's just barely passable, and therefore "mildly adequate"
In Halo 2 or 3, the dual wielding of a plasma rifle and an SMG. The name derives from the Noob Combo, which in the Plasma pistol and SMG, but it is not nearly as cheap. Thus you went from being a "Noob" to an "Adequate Player." This was much more true for Halo 2, where the name was originated, but it still is true and carried over to Halo 3.
Adequate Player: "Oh man, I just buttraped those 2 guys with my Adequate Player Combo."