#1.)  "What makes you laugh the most?"  According to countless surveys, one of the most common things people are looking for is a good sense of humor.  But obviously not everyone finds the same things funny.--So ask your date what makes THEM laugh the most.  It is sarcasm?  Being corny?  Dirty jokes?  What a person finds funny says a lot about their personality and perspective on life . . . AND it lets you know how far you can push the boundaries. 

#2.)  "What's your passion?"  If they can't name ANYTHING they're passionate about, it's kind of a red flag.  And if they DO have a passion, it gives you a good opportunity to ask follow-up questions. 

#3.)  "Is there something you're working toward right now?"  This one sounds a LOT like a job interview, so only go there if you sense there IS something they want to do, and feel passionate about. The idea is to gauge how motivated your date is. 

#4.)  "What do your Saturdays usually look like?"  How someone uses their free time says a LOT about them.  Like if they work on their day off, they might be highly career-oriented . . . or maybe a workaholic.

--Or if they spend the day coaching a youth soccer team, it's a good bet they like sports and enjoy kids.  It'll also give you a decent idea about how available they'll be for future dates.