I’ll start.
my 21yr old DS and his friends accidentally popped a bean bag outside on the lawn (I suspect alcohol was involved). Beans everywhere apparently. DS thought it be a really good idea to vacuum the beans up and spent 2 hrs vacuuming the lawn with my brand new vacuum. Vacuum now blocked with grass, leaves, twigs and polystyrene beans. Goodness only knows what the neighbours thought watching idiot DS vacuuming the lawn.
tell me you stories of daft but harmless things your kids have done.