CD-R + Laser = neat effects
Instructables has a good guide on how to create pretty simple light show effects. Learn more after the jump:

Open Loop Galvo
Posted in Laser Videos, Tutorials at 4:26 pm
I wanted to write a basic tutorial on how to create some simple but impressive laser effects for beginners (like me!) All this setup takes is a computer, an old Laser Disc player and some wire cutters.
