You’ll need a pair of 3D glasses with red and blue (to be more precise, cyan) lenses to watch any of the 3D videos that are available on YouTube or this pool of 3D images (anaglyphs) that’s on Flickr.
For instance, here’s a 3D clip from the popular Avatar movie that you’ll only enjoy if you have the right colored glasses.
Create 3-D Glasses at Home!
The basic 3D glasses are available for around 99¢ on eBay but if you want them right now, you can build your own using a spare CD jewel case and some permanent marker pens.
Just scribble the transparent side of the jewel case with red and blue marker pens* large enough to cover the width of your eyes. The blue (or cyan) color lens is for the right eye while the red color will cover the left eye.