There is no better way to learn electronics and robotics than building your own robots. Twitch by drum303 is a cute robotic pet you can build using an Arduino Uno, 1 x Adafruit Pro Trinket, a 1.2″ LED Matrix, and 3D printed parts. The robot also has a speaker to play audio files, a capacitive touch sensor, and a power supply for the Arduino.
Twitch expresses itself through its eyes, sounds, and movements that it makes. It reacts when you touch it. The instructions are available here.