A meditation on mortality from They Might Be Giants.
Also, a kick-butt rock tune (it's from their fine 2011 "adult" album Join Us).
And a celebration of life.
All of that in a two-and-a-half-minute video. Unless you think the phrase "when will you die?" will prompt questions from your kids that you just don't want to deal with (and, hey, I'm not judging) totally appropriate for the kiddos.
They Might Be Giants - "When Will You Die?" [YouTube]