Here is another modular, educational robot designed to teaches your kids a thing or two about robots. The Mabot robot has a plug & play design. It comes with smart ball modules that can be used to build a variety of fun robots.
You can program and control the toy via drag & drop. Mabot is compatible with LEGO. The kit lets you build 12 robots (e.g. snaker, chicken, explorer, grabber) and control it via Bluetooth.