555 Timers are fun and a great way to start learning electronics
Flashing LED Circuit
A Circuit that flashes an LED on and off.
This circuit uses the 555 timer in an Astable operating mode which generates a continuous output via Pin 3 in the form of a square wave. This turns the LED (D1) on and off. The speed at which the LED (D1) is turned on and off is set by the values of R1 and R2.
This video walks you through building this circuit using a breadboard.