I will be playing in a St Paddy's Night gig. We won't be doing any sectarian stuff though.

"The Boyne Water"? In Scotland it would usually be heard as the tune for "Parcel of Rogues". I think I have once heard an Orange flute band doing it but have never met anybody who knew any Irish words for it.

"The Old Orange Flute" would fit happily in any gathering. It's a satire on sectarianism, not an assertion of it.