Stop Incoming Calls
To stop an incoming call from ringing, press the "Sleep/Wake" button. To send the call immediately to VoiceMail, press the "Sleep/Wake" button twice.
Hide SMS Preview
With Show SMS Preview disabled you will only get a generic "New Text Message".
Go to "General -> Passcode Lock" and enter a 4-digit passcode. After that disable "Show SMS Preview".
Access The Scientific Calculator
Not many people know that you can get advanced features with your calculator simply by turning it sideways.
You can turn it either way (left or right) and you’ll see the calculator go into landscape mode where you see your extra features/buttons.
Since there’s no ability to cut and paste, Apple has integrated email, Safari, and the iPhone, virtually eliminating the need for a clipboard. When I wanted to send the link of my blog to my wife, for example, a small Share button popped up in Safari, which created a new email and pasted the link into the body. Just hit the address bar to find it.