Microsoft has a free "Password Checker" that tests the strength of your passwords. I think most of us know the general rules for a good non-hackable password... letters, numbers and characters, no short passwords, not your cat or kid's name, etc... but this little tool will help you out even more. Or you could just try playing with it for fun.
Now go forth and be safe!
Between Chicago & Milwaukee
Neato-keen; thanks, CK. I'll be changing one of my favorite passwords tonight!

(Sorry, Candy.)