I only just got wind of this upcoming St Patrick's Day related festival.
The Irish Craft Beer Festival will be running at George's Dock in the IFSC for 4 days from 15th to 19th March.
Breweries participating include:
The Porter House
Their website doesn't have much detail yet but you can follow them on Twitter @IrishBeerFest and they are running a competition to win tickets.
ETA: Twitter interaction informs me that they will be open from 12 noon each day!