In reply to notaclue:
If it is a small hole you can tidy up the edges, ( not too regularly as you're eye catches regular lines) screw a larger piece of board with a bit of plastic facing the ceiling to hid the hole , mix up some stiffish plaster and pour it from above into the now blocked hole overfilling it a bit so that it spreads beyond the edges, , and ideally get some strips of something larger than the hole to strengthen it and lay it on top of the plaster in a crisis cross pattern . ( I used old chop sticks !)
When it is set, unscrew the board , and it should come away leaving a slightly proud mend, , sand that back, and paint.
This works well for blocking up old ceiling roses,etc. not sure of the limits on size on this method though.
Sorry as others mentioned, clean up the dust, and dampen he edges of huge mend before pouring in the plaster mix.m
Post edited at 09:36