Grim 80s Sci-Fi After School Special(?)

Help! I'm trying to remember the name of this movie/TV show:

It was a short film or television show geared toward 10-15 year-old kids. 
The plot was similar to a Twilight Zone episode, but it's not the TZ episode titled "The Monsters Are Due on Maple Street" (or the 2003 remake.)
As a housewife is talking on her phone to her friend, her young child runs into the kitchen and grabs some utensils & pans etc. then starts to leave. The mother asks "Where are you going with all that stuff?" 
The child responds "We're playing a game!" 
The mother asks "What's the game called?" 
The kid replies "Invasion!" 
Then the kid runs outside & the mother continues talking to her friend. 
When she mentions to her friend that her child is playing a game called 'Invasion' the friend says that her child is also playing the same game. 
We can assume that the friend is in another town or even another state, and that 'Invasion' is gaining popularity everywhere, as the mother says "I guess 'Invasion' is all the rage!" 
By the end, we learn that the kids, while they think they're playing some type of imaginary game like 'cops & robbers' are actually being possessed by aliens and constructing a device that will facilitate the earth's takeover. 
We never actually see the aliens or their ship. There are no special effects & presumably it was produced on a very low budget. It has only a handful of characters in it: The mother, her friend, the child, and (possibly) the father. 

I saw it around 1985 but it seemed like it came out a few years earlier, possibly as early as 1980. 
I saw it during a single high-school class period in the 7th grade, so I know the length was only around 30 minutes or so. 
Not "Invaders from Mars"