Yep ... up the Moon's gravity well, and then down Earth's. By the time they hit, they're moving at ludicrous speed. Lunar terrorists wouldn't have to aim for specific cities; random bombardment would be nasty enough.
We earthlings could screw up the Moonie’s aim by building yuge rockets parallel to the surface on both coasts aimed toward the oceans. When we detected a rock coming our way we could accelerate the earth’s rotation and they would hit San Francisco instead of New York. Then we’d fire up the opposite rockets to rotate the earth back to normal. Really.