My friend and her brother used to do this (as kids) until they were caught; unwrap their gifts to see what they got and re-wrap them again to "hide the evidence." Their mom caught them one time and she promptly returned the gifts they had opened "prematurely."
My college buddy did this when his mom was out of town a couple of years ago. He and his older sister opened their presents about a couple of weeks before Christmas. Fortunately, their mom never knew (and she will never read this).
I, on the other hand, thrive on the suspense and the surprise of it all. Opening them before Christmas spoils the excitement.
