'The Siege of 318' by Davis Grubb - The toy soldier episode
The Darkroom episode with the toy soldiers was called "The Siege of 31 August" and starred Ronny Cox as the father who ends up under attack by his son's toy army. It was actually based on a short story by Davis Grubb called "The Siege of 318", an excellent horror yarn that appeared in the anthology "Modern Masters of Horror" edited by Frank Coffey.
Stephen King's "Battleground" was similar in plot, but I think Grubb's story was better.
In the story, just like in the Darkroom episode, the young boy in the story gets a box of toy soldiers in the mail. The boy's abusive father eventually angers the little GI's and they really let him have it.