what can one build with bullet proof glass?

How dows one cut it? It is clear plastic from an door about one inch thick.

I've cut 1/4 and 1/2" plexiglass with a fine tooth blade and circular saw. Advance saw a little on the slow side to avoid tear out
and/or splitting.
What did I build? Vacuum chamber out of the 1/2".

What you have is probably polycarbonate. It is a clear plastic material that is bullet proof. You may see the term "Lexan" which is a brand name for the same thing. I once used a 3/8" thick piece to make a hatch for a boat. You could jump on it or drop an anchor on it and it wouldn't break. I had the shop I bought it from cut it to my specifications because they had the right type of blade and equipment to do it. Do a google search for "how to cut polycarbonate" and you should get lots of advice.

thanks all

If it's close to the size of the door frames on your house, you might think about whether or not you can use additional security. A stout frame, lock and perhaps the hinges it came with would be a blessing. If it doesn't, perhaps storm windows that can be secured.
That material is expensive. Times are changing and crime on the rise.

PS: Lowe's cuts the plexiglass that the sell.
Who knows if you might find an employee or manager who would do it for a little$.
The window /glass shop did that for me for cages. A friend had over 1/4" thick he cut himself for a custom reptile cage. He had no experience and it turned out great. YMMV

Not sure but people in bullet proof glasses can throw stones.

Glass houses rather

Make some gunproof glass bullets out of it.

I wonder if we can put it on the front of my car to plow snow?

Depends on how big it is, if it's like the size of car window you might be able to mount some handles on it and make it into a riot shield.

I've thought about putting in plexiglass windows to keep out noise. I also though it would make a good weapons deterrent in case antifa goes off the deep end and starts invading neighborhoods.

But.. my dream would be to build a huge tank that could house two humpback whales that I could take into the 23rd century...