Here's a fun trick that opens up a lot of fun questions. Basically you cut up a playing card (say the four of spades) in a manner that allows you to literally step through the card. Lots of fun :)
Please provide an experience report first.
It was pretty tricky to cut but was really cool to do. My daughter loved it.
I'd recommend this project.
It cost about $0
It took us 20 minutes
Youngest child was 7 years old
This project was very simple (1)