An Irish Sampler, with an agenda

What keeps 'Irish Music' (and Irish Tradition) alive? One answer is the competition-based Fleadh Cheoil na hÉireann
The concept of standard traditional sets, as presented in Foinn Seisiún,has proved popular with many musicians, and is particularly useful for anyone new to the tradition who wants to build up a good repertoire, essential in any session situation.
(These festivals have been going on since 1951 --see All-Ireland Results and Comhaltas Ceoltóirí Éireann Archives for more of the flavo[u]r).

There are other answers... and some of them are also involved with what happens to a musical style/genre over time, and with transplantation to new soils --a theme we'll see repeated with other musics.

This set of examples touches on a number of issues, and is the merest tip of the iceberg/ears of the hippo in my collections of Irish music. And the broader question of Celtic musics is still to come --Scottish, Welsh, Breton, Galician...

Music in the Glen Gardiner Traditional Trio (193?)

Music in the Glen Bothy Band (1976 record opener)

The Story and Legacy of The Bothy Band (1974-79)

Kesh Jig Kincora Ceili Band (193?) --see music, and for fiddle and for whistle and for ukulele...

Kesh Jig Bothy Band (1978 concert opener)

The issue here is that many young musicians feel confined by the strictures of Tradition --and over time the Tradition bends/evolves in unpredictable ways. These include addition of new instruments, innovations of technique, departure from the Rules, interaction with other musics... not without opposition. Most musical genres have mouldy fig proponents, as well as daring innovators.

Oak Tree/Pinch of Snuff Tommy Peoples/Paul Brady (see Tommy Peoples Website)

Toss the Feathers (3 variants) Kevin Burke

Toss the Feathers Matt Molloy (see music, and mandolin tablature)

McDonagh's/Toss the Feathers Matt Molloy

Pigeon on the Gate/Lafferty's Reel/Matt Peoples Reel Kevin Burke/Micheal O Domhnaill (and Matt Peoples by Matt Molloy and Tommy Peoples, with Paul Brady)

Pigeon on the Gate Davy Spillane (and see a list of versions) --also a digression on uilleann pipes

McBride's Moving Hearts (1983 concert opener --dedicated to Sean McBride... see some details)

Glentown set Donal Lunny

...and we really need to think about the vocal tradition(s) and their texts. The examples below are not exactly an objective or representative selection, but each has a purpose...

Thousands are Sailing The Pogues (lyrics)

Waxy's Dargle The Pogues --and here are some lyrics

Nothing But the Same Old Story Paul Brady (lyrics)

The Foxy Devil Christy Moore (lyrics)

Delirium tremens Christy Moore (lyrics)

The King of Ballyhoolie Andy Irvine and Patrick Street (lyrics)

and one that points in the direction of the "mouth music" tradition of Scotland, and underlines the wider Celtic connection: Fionnghuala Bothy Band (lyrics)

A couple more, for instrumental virtuosity:

Double Knuckle Shuffle Tog E Go Bog E

Fred Finn's Reel/Sailing into Walpole's Marsh Andy Irvine and Paul Brady

The Session ("The exchange of tunes is what keeps traditional Irish music alive. This website is one way of passing on jigs, reels and other dance tunes.")

The Celtic World from Internet Medieval Sourcebook

Celt Digital ("The Celtic World on the Web")

Ireland's History in Maps

St. Patrick Was A Gentleman, words and music

LiveIreland Internet Radio