A fun story I haven't been following enough, the Deep Impact satellite rammed into the Temple 1 comet at 6:52 UTC today (fireworks!). /. points to a movie of the impact from the point of view of the satellite. Extremely cool. They also have a highly useful discussion on the amount of energy that was released from the impact:
1 tonne of TNT = 4.184 x 10^9 joule = 4.184 Gigajoules/tonne
19/4.184 ~ 4.5 tonnes TNT
...
1 Kcal = 4186 J
1 Snickers contains 280 Kcal = 1172080 J = 0.00117208 GJ
19 / 0.00117208 ~ 16210.5 Snickers
So the amount of energy released is the equivalent of about 16.2 Megasnickers.
Ah, now I see.
Also from /.: a GIF animation of the impact from the Lowell Observatory; and from the NASA site, what Hubble saw.