In these here parts, we call that a "lazy susan" (no disrespect to Susans the world over...) but here's my two cents (and I've done it myself, so I know it works):
Find a container lid of some sort that's sturdy (hard plastic or metal), flat, large enough to serve as a base for what you want to do and has side walls a tad shorter than a marble's diameter. With the lid turned up, put marbles inside around the rim (hopefully, there's a lip of some sort to keep the marbles at the perimeter but if not, it should still work) and place the table on top. Now, the table should be able to rotate on the marbles. Rather a rough job, but it will work in a pinch.
