You wanna look at the clock at night and you're blindet by the light so that you can't see anything?
This simple app will help you: it displays the time with black background, sets the screen brightness to a minimum and turns off the softkey backlight. You can also determine for how long the clock should be displayed. Default is 1 minute. After that the display turns off and you can turn it on again by pressing any hardware button (e.g. the power button or the volume buttons). The trick here: you don't need to unlock the display. The "NightClock" will immediately be displayed.
You can change the preset display timeout arbitrarily or deactivate the automatic turn off. So the clock would be visible until you close the app.
But beware: if the display is on for a long time this will drain the battery. Do you want to see the clock all night long on the display without touching the smartphone/tablet, then connect it with the power grid.
When you close the app all settings regarding display brightness will of course be reset to their original values.
(Tested with HTC Desire HD / Android 2.3.5) Don't forget to rate this app and don't hesitate to report issues.