I used the basic ideas from this instructable (https://www.instructables.com/id/LED-Beginner-Project%3a-Part-2/?ALLSTEPS), modified it a little, and made somethin' fancy.
Step 1: It Oughta Be Illegal.
So I wired 4 LEDs together in a parallel circuit, powered by a 9V battery. There's an SPST switch in Barry Gibb's crotch to turn the eyes on and off. I couldn't find a 20 Ohm resistor at Radio Shack, so I used two 10 Ohm. I suck at soldering, so this probably looks disgusting, but this is my first project with electronics. That's all I got.