Sometimes you find a book at exactly the right point in your life. I was fortunate enough to read
Have Space Suit - Will Travel when I was a geeky 12 year old boy, and I loved it. If YOU'RE a geeky 12 year old boy, there's a fair chance you'll love it too! He enters this cut-out-the-coupon-and-complete-the-slogan competition (a lot of description of how he intelligently maximizes his chances) and wins an old ex-NASA space suit. He fixes it up, and there are some great passages showing how much fun it is to be able to walk around in your own space suit. Then he gets abducted by aliens, one thing leads to another, and as usual he ends up having to save the human race. It's definitely one of the best examples of this genre.
If you're NOT a geeky 12 year old boy... well, nothing's impossible, but you probably want to read something else instead.