Today Samhain just means "November". I know a story of my older relations being asked about rituals on Samhain by a Canadian and thinking he had crazy ideas of Ireland in November.
Oche Shamhna being the name for actual Halloween. By the 1800s at least, Oche Shamhna was basically just "Snap apple night" where people gathered in one neighborhood house and bobbed for apples. Ironically given the amount of fundamentalist Christian stuff about Oche Shamhna, the only supernatural event associated with the night was that the house would shake from the amount of prayer that night, as you had a bunch of people in one house saying a long string of "Hail Mary"s and "Our Father"s at the end of the night.
Wikipedia is wrong on one thing though, there wasn't any stronger association with the Aos Sidhe* on that night than any other.
*often given as elves or fairies in English, but really meant anything supernatural that wasn't an angel or demon, so included the souls of the dead
EDIT: I just asked my wife and in her area it was "Oche na nll", or "Apple night" and nothing else was associated with it.
Faith writes:
In a way it's been Satan's holiday from its inception
a day to indulge the flesh
Ghosts and bones both contrast with the Chrsitian views of salvation and resurrection
Faith, it's kids asking for sweets at doors.
Edited by Son Goku, : Minor addition