there's an octogenarian singing group based in new england that performs modern rock songs on stage. seriously. stop laughing. once you get past the novelty, it's actually a quite tender concept. if you live out there, they're called "young at heart" (except with the "at" symbol replacing the spelled out "at" - damn you, blogger).
anyway, here's one of them singing "fix you" by coldplay.
as one of the commentors posted, the song is usually chris martin singing about the future.
however, this version by "youngatheart" was supposed to be a duet. but one of the singers died of a heart attack weeks before the performance. so the lead carried on and sang the song by himself, and without changing any words, it became a reflection about missing people in your lives by someone who has lived his life through.
it's really poignant.
here's them singing "schizophrenia" by sonic youth. i betcha thurston moore and kim gordon really dig it.
and here's a video of them singing "i want to be sedated" by the ramones, although it comes off as really cheesy, to be honest.
still, i wish there were more out there.