Logic Puzzles

So if I forgot the story the host told me, my chances are 1/2 because I don't know that they once were 1/3?

if you were presented with two doors, without all the previous knowledge and the door opening nonsense that's gone on before then yeah - I think so :)

Try running this ten times or so, first keeping then changing your choices and see what your figures come out at:
http://math.ucsd.edu/~crypto/Monty/monty.html