Quick Tip: Removing Your Keyboard Without Using the Back Button
"Android: If you're ever in a situation where you need to get out of the Android keyboard, a somewhat hidden shortcut will close it right up: just swipe from the top of the keyboard to the bottom."
Here's a quick tip to use the next time your keyboard annoys you! Just swipe your keyboard from top to bottom and it will disappear. Works on most phones that run Gingerbread and Froyo but will not work on HTC phones. A quick and easy way to get rid of that keyboard, especially if you just don't want to spend those few extra seconds moving your thumb to the back button!