I'd like to express my deep gratitude to a member of the Columbus slow sessions email list who directed my attention to the Riley School of Irish Music tunes page, where I found a slow recording of the beautiful slip jig The Snowy Path. The slow recording makes the tune almost trivial to pick up by ear; just start on F# and play in D major and if you know the tune at all you'll have it in no time.
This tune was composed by Mark Kelly of Altan; you can hear it on their album Harvest Storm, including a gorgeous flute solo by Frankie Kennedy. Click the Amazon ad on the right to hear a short sample of Altan's recording of this tune.