Hey Bob! Good to see you too. How’s Uncle Sam treating you? Have you started teaching again since your move? (you did move, correct?)
~W
Welcome back, Bob.
We do an obstacle course for the kids, too. They love it. They also love some of the other games we play (shark attack, and so on). I like the bubbles idea. We have summer camp coming up and I think that will go over well with the kids. Any other warm weather, outdoor fun training ideas?
Surrender yourself to nature and be all that you are.
Kids Games
At my first tang soo do studio, we’d play a game with the littlest kids (age 5-8) called “Poison Ninja Stars”… Really it was dodge ball using focus mitts or whatever we had soft on hand. But they loved it, cause if they got hit they were “dead” and had to sit out. The last one standing could come up and help the kyo sa/ sun beh throw.
It was a great game for agility and coordination and wore out the kids on Friday nights. 
The best way to win a fight is not to be there in the first place.
Similar techniques
We use a sandbag instead of ball bearings, but it is the same idea 8^).
Another thing we do is line up with one person in front. Everyone takes a turn at throwing 3 attacks, and the person up front has to defend. It is good fun, and you sharpen your defence while learning how to combine movements.