10 Megajoule Weapon

Thanks again! I guess my problem is that I understand it when a bomb is shot because a highly explosive shell is launched into the air at a angle that will allow it to go up then down into its intended target. Does this do the same thing whenever it "projects" its projectiles? Say a tank was going down a street inside a town would the projectile go over the towns buildings then land or hit the tank missing everything else in its path?
A railgun will shoot in a straight line, like a rifle. What you're describing is a mortar round. Again, there's no bomb involved with railguns. Just pieces of metal moving really fast. The "explosion' is caused by the sudden release of kinetic energy as the object moving at very high speed hits its target (remember energy=mass x velocity squared, so the amount of energy imparted increases exponetially as the speed increases).
This seems a bit large... I mean, coservation of momentum is a bitch---if you mounted one of these rail guns on something that weighs 10^6 kg, you'd end up with a backwards velocity of 30 m/s, which is like 80 miles per hour.

I'd imagine that they can damp the kick somehow. Anyone know how they deal with this?

I'm sure the 64 MJ figure is the amount of electrical energy that they dump into the gun upon firing, not the kinetic energy of the projectile.
Why so sure? A bit of reading indicates that rail-gun ratings seem to usually be muzzle energies.
For example, regarding the 10 MJ test, the Navy says:
Office of Naval Research said:
On January 31, the Office of Naval Research made history with the muzzle velocity of its electromagnetic railgun at the Naval Surface Warfare Center Dahlgren Division. Fired at 2,520 meters per second, the shot generated 10.64mj of muzzle energy.