FRIDAY: For many of us, going to see Garrison Keillor’s “A Prairie Home Companion” recorded live was one of the few times in our early teens when both we and our parents could agree on attending the same event without rancor. But Keillor’s getting up there, and it seems more likely we’ll be sharing “This American Life” or even some yet-to-be produced program with our own kids. For now, thank goodness, Keillor and company are…