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.While most of the time, the back button should get you out of the keyboard pretty easily, the back button is one of the most unreliable, annoying things about Android. Couple it with an app that has a poorly-built text box and you've got yourself a situation where the keyboard just won't go away when it's supposed to. For those situations, there's this handy swipe gesture.
If you don't get it on the first try, you're not alone — sometimes it can be a little finicky. The best way I've found to think about it is to hold the "T" key for just a split second, then drag your finger down past the spacebar. Usually this'll get rid of that pesky keyboard nicely.
This shortcut works on the default Android keyboard for both Froyo and Gingerbread, as well as many third-party keyboards, like the very popular SwiftKey.
For those of you that aren't fans of the swipe gesture, you can also press and hold the Menu button on your phone to hide the keyboard. This also shows the keyboard, too, which is nice if it doesn't come up automatically for some reason.