I read this great book over the weekend that reminds me a lot of Freakonomics. It's called The Drunkard's Walk: How Randomness Rules Our Lives. If you haven't heard of Freakonomics, it was a runaway bestseller and described how economics intersects with everyday life - everything from the drop in New York City crime rates to the fixing of Sumo fights.
The Drunkard's Walk starts with a basic primer on probabilities with a little history lesson thrown in and then quickly moves in to some real world examples.
One of the more interesting ones is The Monty Hall Problem. Monty Hall was the host of a TV game show called Let's Make A Deal. He would offer contestants the chance to win a car by picking one of three curtains. Behind one of the curtains would be a car and the other two curtains would have a goat. After the contestant selected a curtain, Monty would open one of the other curtains and reveal one of the goats. At this point, Monty would give you the chance to switch the curtain you selected to the other remaining one. The question is, what would you do? Since I was a math geek, I of course knew the answer was it didn't matter, you had a 50-50 chance at that point of winning the car. Apparently an overwhelming majority of math professors in the US also agreed. And that's where we would all be wrong. You're actually far better off switching to the other curtain. Here's why. If you select Curtain 1 and decide not to switch, you have a 1 out of 3 chance of getting the car. However, if you do switch, you have a 2 out of 3 chance of getting the car. The Wikipedia link above has much better explanation.
Other stories covered in the book are Wine Ratings (i.e. is there really a difference between an 89 and 92), why polling results are often misleading and where they get the +/- numbers, and how you can improve your SAT scores just by taking them a few more times.
Very good read, even if you're not a geek.