This small robot moves by rolling. Very durable, it can take small bumps and falls with no problem. Using an iPad you can directly control Sphero, or program it to follow a set of instructions using an interface simular to Scratch.
Using a system based of the Lego brick system, you can easily build complex robots and other mechanical devices. Use the EV3 control module to program actions and behaviors, or use the Mindstorms App for iOS to directly control or advance programing.
Not sure what to build? Take a look at some of our books and ebooks on Mindstorms.