I'm sure Ballyhooly is lovely! There are two "apparently"s in there. And the entry is marked as "DRAFT ENTRY June 2008," for whatever that's worth.
But yes, as recently as 2002 — "It was pandemonium. It was Donnybrook Fair. It was all ballyhooly let loose." (J. O'Neill, At Swim, Two Boys), and as early as 1837 — "By Jasus! he gave him Ballyhooly, the d—d insolent son of a sign-painter!" (Tait's Magazine)
1. Does anyone seriously use this word to mean "hell"?
2. Also, I grew up four miles from Ballyhooly (whose name means "town of the ford of the apples") and that bit about being 'notorious for faction fighting' is completely bogus. Apparently even the august OED is not above stooping to the occasional bout of ugly racist stereotyping.
The OED says: "Apparently from Ballyhooly (Irish Baile �?tha hÚlla), the name of a village in County Cork, Ireland, apparently formerly notorious for faction fighting, although this may reflect a later rationalization of the word."