[Say, it isn't that bad!]

Combination 66a) The Greater Matrioshka Horror
Template Toolkit 3: Starship Crew and GURPS Dungeon Fantasy 21: Megadungeons

Once, an immense, physics-and-sanity defying creation of some elder race for whom tech level 13 was full of amusing trinkets. Wrapped around a single lone star in a near-empty region of space; the matter of dozens of stars, over a thousand attendant planets, tens of thousands of Oort Cloud objects, and countless interstellar miscellany went into constructing this monument to a species whose past existence is now the merest trace of a whisper of a rumour.

All except for the physics-and-sanity defying wreckage and shattered ruins of a structure light-hours across.

Now it is the haunt of mercenaries, pirates, scholars, small civilizations, madmen, refugees, ancient mechanisms still struggling to fulfill some arcane purpose, rogue defence mechanisms, and worse. And it is to this nigh-endless ruin that your crew of mercenaries, pirates, scholars, madmen, refugees, and/or other have come.

With good luck, you'll be able to pay off your starship, and retire young. With bad luck... well, you won't have to worry about all that debt.