If you have a digital wristwatch that shows the time as little black numbers, you are using polarizing filters. Those numbers are created using Liquid Crystal Displays, or LCDs. LCDs change their polarization when an electric current is applied to them. So, they can be made to go from clear to black by having an electronic circuit hit them with current at the right time. When you put enough of these small LCDs together, you can form letters and numbers from the little LCD segments.
Many sun glasses use polarizing filters.
When light reflects off of shiny surfaces, we refer to it as glare . Glare light happens to be quite polarized. Sun glasses that are polarized at a right angle to that direction are especially effective at reducing glare. Stereo movies such as Disneyland's Captain EO , use polarizing filters to separate the left eye view of the movie from the right eye view. There are polarizing filters in front of each movie projection lens.