[VanShuyten]

I lost the URL for a great Japanese animation of a planet-killer striking the earth. Very high quality and, somehow, calming. If the Big One hits, I won’t even feel a thing.

[Calvin Locke]

Not really applicable to wiping out the dinosaurs, but Sandia.gov had some interesting simulations last year of what might have occurred at the Tunguska event.

Apparently craterless, but it still dragged along a powerful local shockwave.