Man, David Letterman has aged a bit…

Also blunt force trauma, choking, or a fatal dose of ennui through observing the dissipation of a once solid object into insubstantiality and analogizing it to the ephemeral nature of the mark one leaves on the world.

I suppose hypothermia, frostbite, impalement (if pointy), and crushing (if there were enough of it) could also be ways that one could meet their demise via dry ice.