I made an additional half-dozen swords so that I could take a good number to my family reunion. Gave 'em to the six-twelve years olds and told 'em no head shots, and they played pretty much nonstop for two days with only one injury (busted canker sore).
duh. You could give kids water guns and they will play with them for days. As long as it is a toy that lets them feel like they are inflicting some kind of harm they will love it.