A Tiny Autonomous Droid With a Dedicated Party Mode
Maker heychaostheory built a small wheeled mouse droid with a 3D-printed body, ultrasonic obstacle avoidance, an Arduino Uno, motor control, and flashing LEDs. It can drive around on its own while avoiding objects.
Then there is the extra feature: a dedicated party-mode button. Pressing it triggers music, turning a practical autonomous robot into a mobile party machine on command.
Details: Hackaday ↗

Obstacle avoidance is useful, autonomous driving is sensible, and then someone decided the robot also needed a dedicated party button. That priority list feels exactly right for this droid.