[jazzyjackson]

+1 for lego mindstorms, you can build all kinds of robots without dealing with solder and learning i2c protocol etc. I was building autonomous rover

i can also recommend the book "Mindstorms: Children, Computers, and Powerful Ideas" by Seymour Papert. it's pretty short and gives a great way to teach kids programming by encouraging them to put themselves in the computers' shoes, so to speak

once you have a collection of motors and sensors from lego robots and want to repurpose them, you can totally hack them into working with arduino, and i believe there are also projects to write C code on the lego mindstorms brick if you want to dig deeper that direction