Good Day!
Do you wear prescription glasses? Do you like 3D movies? Do you hate having to wear TWO pairs of glasses to watch these movies? DIY to the rescue!

Create a pair of polarized Real3D clips so you can comfortably watch 3D movies with prescription glasses.

You need:
A pair of clip-on sunglasses that fit your prescription lenses. $15 at walmart... be sure you can pop the lenses out.
TWO pair of Real3D movie glasses... yeah, you paid the 3D premium for them, don't recycle them next trip. $6-$10 depending on your theater's markup.
Prescription glasses. $GDP of a small island nation. (just kidding.)

Step 1: Prepare the Lenses

First, place some masking tape on the lenses of the clips and one pair of the 3D glasses.

Then, using a marker, write which lens is left and which is right on each pair, and draw an arrow pointing UP on each piece. It doesn't have to be perfect but try to be as precise as possible - the arrows on each same-side lens should point in exactly the same direction. This is important for two reasons:
1. FIT - so the 3D lenses will fit once cut to shape and
2. POLARIZATION - the 3D lenses only work in one direction, if they're turned off-axis too far, they won't work at all.

Pop the lenses out of the clips.

Step 2: Obtain 3D Filters From the 3D Glasses

I wanted the WHOLE filter lens from these glasses so I didn't cut them out with a hobby knife. Instead, I cracked the frames apart.

First, remove the temple bars.
Then, cut off the temple bar hinges.
In the gap left by the piece you just cut away, wedge your scissors in and twist, separating the two halves of the glasses frames.
Then simply remove the filters from the now separated frames.

Step 3: Cut the Filters

Place the L and R lenses together, and align the arrows so they point the same direction. Make sure the filter fits all the way around the clip lens, and then carefully trip away the excess filter lens until it's the same shape as the clip lens.

Repeat for both sets of lenses.

The last picture is upside-down, but you can see I've done the Left lens but not the Right one in that shot.

Step 4: Fit and Test... Then Off to the Show!

Fit the new 3D filter lenses into the clip frames. They should go right in, but in case they don't, very carefully trim away any excess and refit the lenses until they're snug. If you're very confident in the fit, you can use a little super glue to permanently affix the lenses in place. (I did not yet....)

Place the clips over your prescription glasses to ensure fit and that they won't rub against your lenses and possibly scratch them. That would be double plus un-good.

Then use the second pair of clips to ensure you have the polarization right.
1. Orient the 3D glasses as though you would be using them, then look through your clips and the 3D glasses, they should just appear a darker shade of gray/sepia.
2. Orient the 3D glasses as though someone else wearing them is facing you. Look through the left lens of the clips - the right lens (your left) of the 3D glasses should be black, the other should be clear. Look through the right lens of the clips, and the left lens (your right) of the 3D glasses should be black and the other should be clear.

Look at the images for a better understanding....