Several tapes of old old Clancy Brothers and Tommy Makem albums; that Alnwick&Tyne one I asked for the lyrics to a while back; Les Compagnons de la Chanson; Les Frères Jacques. That's for me. For the twins, I have several tapes of old old children's songs (Ed McCurdy, Pete Seeger), and one by John Lithgow that is a howl.
I keep the radio buttons saved for NPR, NPR, NPR, the local university station that plays strange stuff, and one regular old station that plays Oldies. But I usually keep in on NPR since my commute tends to be when I get to hear the news anyway.