Interestingly it was originally a Christian holiday (hence the 'saint') that went mainstream as an excuse to drink. Patrick would have been irish, certainly, but the popularity is widespread. Where the heck leprachauns fit in I'm not sure.

Interesting point, however, many won't celebrate it as it happens to fall in the period of Lent, which is a time of fasting and reverence.

I was hoping for shamrock cookies... but oh well