The answer to this question about blockers and summoning sickness, reminded me of a seldom treaded area of the combat phase, which has caused confusion in a number of games.
When blockers are declared, the attacker chooses the order damage will be assigned to them. Then, they assign damage, assigning at least lethal damage to the first one in line, before moving on to the next, and so on.
Can spells be cast between the ordering of blockers by an attacker, and the damage being assigned?
for example, is blocking a 4/4 creature with 4 1/1 soldier tokens, and then casting Giant Growth on the "first in line" so the other 3 soldiers survive a legal play?