Make your own 3D passive gaming glasses

If you have a 3D TV with gaming mode, you can set the TV to show 2-player games full-screen.  That is, player one will see only their section full screen, and player 2 the same.  Unfortunately, it means buying extra glasses for ~£30 each.

However, if you have a passive 3D TV, you can make your own glasses.  Simply buy some cheap (around £1 each from the cinema) passive 3D glasses.  You can now remove the LEFT lens from one and the RIGHT lens from the other, and put the lenses back in the other pair, so you have one air with two LEFT and one pair with two RIGHT lenses,

Now when you initiate the 2-player gaming mode, player one wears the glasses with the two LEFT lenses and player two wears the glasses with TWO right lenses.

Tried on a passive Phlips 47PFL6907T/12 television.  Please let me know in the comments if it works for you and what TV you tried it with.