The Dubliners generally stick to the same patter they've been using for years; and if it works, why mess with it? Still makes me laugh.
A few from Barney:
"This is an Irish solo... There's two of us going to play it."
"This next one's a mandolin duet. It's an Irish duet... There's three of us going to play it."
"For those of you who haven't heard these tunes before... well, this'll be the first time."
"If I speak too fast for you, you'll have to listen to me quicker."
And one I heard John use a few months back:
"We've been going nearly 50 years. As Barney always says, it's too late to stop now."
I recall a couple of gigs when the late Ronnie Drew got a little annoyed when the audience used to murmur along with his well-known anecdotes and gags, kind of like geeky students quoting Monty Python sketches from memory!
Christy Moore and Finbar Furey are also masters of banter and heckler-management.