Materials: paper 3D glasses, old sunglasses, scissors, scotch tape, tweezers.
Macbook Air unecessary :)
Step 1: Take the old sunglasses
Use tweezers to remove the screws holding the lenses in place.
Take a piece of tape and cut it vertically into two thinner strips.
Use one strip to tape the two pairs of glasses together at the nose.
Save the screws to rescue your other sunglasses.
Oh, did I say that's why i wrote this instructable? :)