We had 4-square most of the way through my high school in Queensland, but with a tennis ball, and there were usually up to 15 people playing (and sometimes more if we could define enough squares). You also had to bounce the ball in your square before it bounced in someone else's square, and you could volley It'd either go in a rotation like 4-square with the dunce (lowest person) getting eliminated if they lost, or with lives. In lives, you didn't rotate, so it often ended with the final 2 playing each other with 2 or 3 empty squares in between.
We were all pretty skillful by year 11, needless to say
We also had a game called Bash Ball in year 9. It involved throwing a tennis ball against a brick wall, aiming at a plaque. If you hit it, you got to randomly beat everyone else in the game until they touched the wall, but if you went to catch the ball and dropped it, everyone else bashed you 'till you touched the wall. If you were at the back of the pack, this was a Bad Thing.
That game ended when I broke my arm...I rode a guy for a screamer of a mark (If you're not Australian, that means I jumped on his shoulders and caught the ball), then fell right down onto concrete.
We had Yo-Yos in year 8, and knitting for a short while in year 9.
Oh, and I was the height of Year 7 fashion in my black-and-white striped Shaquille O'Neal Reebok Pumps!
And, of course, when we got bored of all of the above, we didn't go without our fair share of backyard cricket. In fact, in 3rd year uni, we still play a hell of a lot of backyard cricket. I'm pretty sure that doesn't count as a fad.