Many of these devices can be made at home. Just go to the local hardware store or home depot etc. I have made several which I know inquisitiv would enjoy. I used boards to make a trap that locks my balls onto the board so my wife can step/stomp, stand on them or whatever. For the plexiglass cylinders and crushers we have a place that specializes in plastics-

http://www.tapplastics.com/