Tommy Makem has some brilliant ones, that never get old.

On getting little response on a chorus: "Let's all join hands and
contact the living."

When something crashes in the back of the room: "Hit him again!"

Or "...the Irish gals, they go out sowing their wild oats
all week then go to church on Sunday and pray for a crop failure."

At a Boys of the Lough concert, after a particularly long introduction
to a tune, one of the other lads said that resident scholar Cathal
McConnell had been diagnosed by his physician as suffering from
'Alcohol induced verbosity.'