Did this in 2000 when I worked in a kids club.
‘skate board tug of war’ 2 people kneel on skateboards facing each other then tug of war rules apply.
‘Collapse’ 4 or 5 large boxes, children in teams of 2, stack boxes ontop of each other but one hand has to stay behind your back.
‘Decathlon’ mixed events such as 100m sprint straight onto hop skip and jump, throwing water bombs till you hit a target that kind of thing. End with a paper burst copied off gladiators, we used an old roll of backing wall paper, pre cut a cross in the middle.
‘land ski’ using skateboards and 2 strips of dowl (we had this bamboo stuff) negotiate between flags/cones, falling off 3 second penalty, we did this in the park on that foamy rubber stuff they put under play equipment.