The other day, when idly browsing eBay, I found a listing for "POW! The Cannon Game For Boys".
I suddenly remembered it. That very game had been one of the stack we used to play when we went down the coast for the holidays.
(There was also a large pile of dog-eared 1960s comics, all of which I pored over at very great length. They included a colour reprint of the one that inspired a Mythbusters stunt.)
To be honest, we didn't actually play "POW!" very often, since it was a pretty dud game. It had little stand-up cardboard soldiers and marble-shooting spring cannons, which sound like a recipe for a diverting piece of entertainment. But the cannons had very little power, and the cardboard base was bouncy enough to make the whole exercise pretty random.
Still, y'know, it wasn't bad for 1964.
("POW!" certainly beat the heck out of the two-years-older "Squatter: The Australian Wool Game", which provided an intoxicating mix of incomprehensibility and tedium to hundreds of thousands of Australian children, possibly as a way of preparing them for the task of filling out income tax forms. If you need a lot of little plastic sheep-head tokens for some other game, though, "Squatter" can't be beat.)
The vintage also explained the "For Boys" thing. Sexism in toys is still very much alive, but I reckon the 60s was the last time it was actually made clear in big words on the box.
Until today, though, I had no idea that "POW!" had a sister game. Which was largely the same, but at the same time completely different.
I give you: "WOW! The Pillow Fight Game For Girls"!