The cub wanted to go to a spreay park with water cannons where the backup day home apparently took him. In an attempt to find it, we instead found a community centre with some sort of festival going on and a bunch of different types of bouncy castles. This sufficed for alternate entertainment.
There actually was a spray park there with water cannons too, but it was so crowded with kids that the cub couldn't get a turn in edgewise.