Takeaway #1: We now have a pool of tools for hacking, but I have a query:
Were your children taking something and questioning its assumptions and changing the toy to match their beliefs? I think hacking is a natural way to learn much like walking and talking, probably not overtly analytical like Chad's adult definition of hacking. Are your kids showning you that hacking is just a larger form of pattern making. That is what the brain does so very well.
Takeaway #2: We need to hack our children's idea of play. Is that a make or a hack?