Irish traditional music session

Irish traditional music sessions are informal gatherings at which people play or sing traditional Irish music. Sometimes there are more-or-less recognized session leaders; sometimes there are no leaders. The general approach is that someone starts a tune, and those who know it join in. After a while, the tune comes to an end, and someone else starts another tune. Sessions are often held in pubs (with the hope that listeners will buy drinks for the musicians). Sometimes they are held in homes or at various public places.