In the news

54,000 km/h / 60x60 s/h = 15 km/s

KE = 1/2 m v^2 = 1,125,000,000,000 J, equivalent to 269 Tonnes of TNT in the usual measure of explosions. i.e. only a little more than a quarter kiloton, about equal the smallest nuke in the US arsenal.

Interestingly, would have got upto 11.2 km/s of its velocity from falling into the Earth's gravitational field, so would have been wandering through space at less than 4 km/s - too slow for it to have come from very far out in the solar system.

It seems people are revising their estimates upwards. http://www.space.com/19822-russian-fireball-biggest-explosion-century.html

speed up just a bit to 64,800 km/h = 18 km/s
mass up vastly from 10 to 7000 tonnes!
and energy up even more vastly to 300 kilotonnes TNT!!

Putting those speed and mass numbers into 1/2 m v^2 only gives 270 kt TNT, so i'm not sure what's going on here. Maybe people are trying to map back from the blast effects to the energy using scales calibrated for nukes, which unlike meteorites put a lot of energy not into blast but into high energy particles. Also the cylindrical blast from this meteorite would decay with distance more slowly than the spherical blast from a nuke, though that shouldn't be confusing the distant infrasound stations.

So i'm dubious.