Not long now - Tradfest 2015 runs from 28th January to 1st February in Temple Bar. Although most of the music is Trad, you don't have to be a Trad fan to enjoy this. The venues and atmosphere are a major plus, and this really is the right time of year for a Trad festival. Feck it, I hope it rains, because it'll just make it all the cosier.
As is the way these days, there's a foodie add-on (Temple Bar Taste Trail), a photography exhibition, talks, workshops, and free events in many of the local pubs (Tradfest Music Trail). If you life craft beer I'd recommend the Norseman, and if you don't like craft beer I'd recommend the Norseman and drinking craft beer. The Porterhouse should be good too.