Little Bits are the tiny circuit pieces that you can piece together with magnets. They are based on the principle of giving an input in order to get an output, and all you need to get started is a blue power, pink input, and green output, Each circuit does something different, so it allows a host of projects if you have the right bits.
Two of the best bits are the servo and the motor as they give you a host of options for movement, and that's what their current invention challenge is all about. Create something new that moves! Check it out at https://littlebits.com/challenges/make-it-move