I recently stumbled upon the Monty Hall problem at Wikipedia. I've seen this problem before, and have always used good old bayes theorem to solve it. Since, I was hacking at some boring regular expressions and needed to take a break, and also Wikisource site has C/C++/Java and Perl simulations but none in LISP, so I decided to try my hand at it.
Since, I am not some 'uber-lisp-hacker' this is not the most efficient code one can write and if some uber lisp hacker finds this , maybe he can improve it.
Anyway here is the code..