The hole measures 65 metres across, and based on images taken at a variety of sun angles, the hole is thought to extend down at least 80 metres. It sits in the middle of a rille, suggesting the hole leads into a lava tube as wide as 370 metres across... Since the tubes may be hundreds of metres wide, they could provide plenty of space for an underground lunar outpost. The tubes' ceilings could protect astronauts from space radiation, meteoroid impacts and wild temperature fluctuations...
This is reminiscent of the "doorway" found on Mars several years ago, but this discovery seems to be more clearly defined. More details at New Scientist, via NAACAL.