Yep, I'm from Northern Ireland and it's pretty much go into the centre of Belfast and get drunk all day. The trick is to get started early because if you don't then all the other drunk people are very loud and annoying, whereas if you are as pissed as everyone else then everyone's your best friend.

It's also notable for being the first day of the year where you are likely to be asleep before it gets dark again (maybe 6.30-7pm in March).