There's a Clancy Brothers song to an old Gaelic air; I think the title may be Air Fol-lol-lol-lo.

Probably not the songs for you or the venue, but since the list has been started:

O Siem by Susan Aglukark.
Everything is Beautiful by ... ol' Whatzizname.

And then there's:

Erin-go-bragh (racism? bigotry, anyway - course, it ends up with a cop getting his lights punched out, which might not be the sort of thing you wish to encourage).