I love fun web games that have neato results statements like:

The fireball is below the horizon. There is no direct thermal radiation.

Whew...except...this is a real time, real outcome widget to figure out how you would be affected in the case of an asteroid strike. It takes into account the angle of the strike, the density of the object, your distance from the impact, etc. For the true worrywort amongst you from the good folks at the University of Arizona's Department of Planetary Sciences.