Control your car lights using Arduino.
My project is an a voice assistant for space/home monitoring while you are away or not nearby.
Make an Alexa clone using Raspberry Pi 3 and use it to control IOT RGB Lamp (Arduino Nano + ESP8266) that supports Philip Hue commands.
Alexa controlled timers at a glimpse. A really fancy egg-timer with added temperature control.
Rainbow colorful flashing RGB LEDs; Soldering practice for beginners or electronic hobbyist. Could be a nice present for kids.