Here in England - I'd have trouble telling you when the Queen's birthday (official or real) was. I think this thread has summarised all the important ones, though. One thing that I've noted about all this fake irish crud from last night, is that I'm only aware of it having really happened in the last 2 or 3 years, and mainly as some kind of Guinness marketing campaign. I suppose the other one that gets celebrated in England is Burns Night (with Haggis and Whisky - not that I really need an excuse to drink a decent scotch!), but I don't think that's particularly widespread, and it may well be that all the people I know have a scottish connection.

(at this point I'm thinking of Bill Bailey when talking about the terrorism threat, and somehow he'd ended up imagining a world without cheese: "the Welsh national dish would be toast!")