A keyboard that does nothing.
Yes really.

This keyboard is useful if you have an external bluetooth keyboard paired with your phone and you want to stop the on-screen keyboard from popping up all the time.

To use go in to keyboard settings and enable null keyboard and then pick it as your input method. No keyboard should appear until you change it back.

NOTE: Samsung galaxy tabs running the latest android have an issue where the keyboard is frequently switched back to the on-screen keyboard. As far as I can tell a fix for this needs to come from samsung not from me. Even if it's something I can fix on my end without a tab to test on there's no way I'm going to be able to figure out what it is.