Thanks to A Tangled Web: Plastic Paddy Ignorance for a copy of the flag:
More information about the history of the day itself can be found at Wikipedia: Saint Patrick's Day.
There are some particularly interesting comments about the way the day is celebrated in some countries on the talk page:
As a native-born Irishman, a lot of the paddywhackery, especially American paddywhackery, associated with Saint Patrick's Day makes me want to puke. For one thing, no one in Ireland--except for certain entertainers, whose livelihood is gained by pandering to the expectations of green-clad Americans--would ever say "Saint Paddy's Day." It should be remembered that the first to celebrate St. Patrick's Day in America were Protestant "gentlemen," who dined at various good-quality inns; they wore the color blue, that color being then associated with the Feast.An interesting perspective on how a day of tradition and veneration has been bastardised in the US to become an excuse for a piss-up.
The British government encouraged the celebration of Saint Patrick's Day as a "national day," because (at least, at the time) it had religious rather that political--i.e. rebel--connotations. Trooping the Colors at Dublin Castle was the annual contribution of the British authorities. It was essential to reinforce the ideology that even the "mere Irish" were happiest when serving their British overlords.
In New York, the parade was soon taken over by the Ancient Order of Hibernians, a right-wing, (some would say Fundamentalist), and certainly male chauvinist Catholic organization, who wanted to define for themselves what constituted "Irishness," an ethos very much removed from that of today's Irish population, as evidenced by the opposition to gays and lesbians. Seen from outside, their conception of "Irishness" is closer to that of the 19th century than to that of the Ireland of today.
But, in the United States, apart from the ridiculous practice of dressing up in green, the most odious aspect of St. Patrick's Day is the apparent license it gives to all to drink to excess. (The term "drowning the shamrock" comes from the tradition of the "Protestant gentlemen" putting their shamrock in the glass when the last toast was drunk.) When I was a child in Ireland, the day was celebrated primarily as a religious holiday, with obligatory attendance at Mass for Catholics. In those days, the public houses were shut on St. Patrick's Day. Even this year (2006), the off-licenses (liquor stores) were requested not to open until 4:00 pm, a request that was largely honored. The parade, during my childhood, was an industrial parade, intended to show Ireland's merits as a base for industry--another idea from Taoiseach (prime minister) Seán Lemass, intended to improve Ireland's miserable economy.
However, in the United States, those who would be Irish consider the day as a "National Let's-All Get-As-Drunk-As-We-Can Day." Greeting cards, including ecards on the Net, are laden with the stereotype of Irish drunks; no other ethnic group in the United States would condone this practice, which can often quickly lead to racial slur.--PeadarMaguidhir 11:13, 9 July 2006 (UTC)