One example of the problems I ask all candidates is this softball: Write code (in any language, or in psudocode) that determines if a word is a palindrome. There is a very quick way of doing this (str == str.reverse) and then there is the writing of the actual algorithm. If someone gets the quick way first, they get bonus points, but we still ask to see the algorithm written out. When I asked this of the 15 - 20 women I have interviewed, I noticed they second guessed themselves too much, and got intimidated easily. They are not confident (dare I say egotistical?) and back track a lot when we ask them verbal questions.
It could be my experiences only, and there are of course men who are the same way, but what we look for is this: The ability to confidentially and quickly put something up on the board, look it over, realized you fucked up (because almost no one gets things right the first time), correct it, look it over again, realized you fucked up (because very few get it right on the second try), and correct it. Be done with it, then describe all of the other things you were thinking you could do with it. It shows you aren't pressured by mistakes, you own up to problems, quickly fix them, and think of ways to better it later on. This is a quality I don't find in the women I've spoken with (with one exception). It seems like they don't understand shit happens, no one is perfect, and that's what you have a debugger for.