It's a pity that the venues part of that website is a bit less organised than the magnificent tunes section! (Duplicate and misleading entries, etc.) HERE's an active link. Then click the search tab, bearing in mind that Ireland and Northern Ireland ae listed separately in alphabetical order, so well apart from each other.

In Belfast, John Hewitt's is one of the newest on the scene and among the best known. It inherited some of the musicians from the Liverpool Bar, when that building came down. But as with any other listing, be sure to check under the "comments" tab, where you will find that it also has a Sunday session (4pm I think) in addition to those listed. When I was there, Sunday was the best.

The Kitchen Bar (Fridays) has a long-established Belfast session. And for a real down-to-earth session, fine Guinness etc, you can't beat Pat's bar in the Docks. Again check the website for details, and make sure to look at the comments. There's a similarly rough-and-ready session (similarly fine Guinness) and seriously fine playing at Fealty's in Bangor. (Get to Fealty's by 9.30pm if you want a seat near the music - bottom right if you're planning to play, or bottom left if you're going to listen. The session goes on to about 12.30am; last orders a little later.)

The Skerry at Newtown Crommelin is listed as having Wednesday and Saturday sessions. Saturday's likely to be a much better bet than Wednesday, but maybe phone first as it's far from the beaten track (but in the middle of spendidly scenic country).

Te other one I would single out for mention is the Crosskeys, near Portglenone - again listed on the website. The music is mostly at weekends, but you'd need to phone as it's not every week. On Sunday afternoons there is often a workshop for young and very young players, and this is worth catching. You're likely to hear musicians who will eventually be in contention for all-Ireland honours.