To many, Samain is a very solemn festival.It is the time when the Earth's crust is thinnest; when communication with the spirits of the dead are easiest. To others it is the time of the last harvest; of the choosing of the animals to kill for meat to last through the Winter. Yet others would light great bonfires to encourage the return of the Sun in Spring. (You must remember that in those days the 1st of November was the 9th month of the year.Only ten months in the year in those far off times! So it was the start of Winter.)
Children, of course, will celebrate Halloween; something altogether different.That was (and still is!) All Hallows Eve, when the next day all the saints, who did not have a feast day of their own, were "feasted" with a Holy Mass.
I'll tell you how I celebrate Samhain. I light a big fire in my back garden, and get drunk!