This small snippet will allow you to use different color schemes (CSS stylesheets) depending on the time of the day! Its not a hugely complicated piece of code, but very creative! Most people have never even thought of the idea!
PHP:
<?php
// If the time is past seven O'clock then use the night stylesheet instead!
if (date('G') > 19 || date('G') < 7) {
echo '<link rel="stylesheet" type="text/css" href="/static/css/default_night.css" />';
} else {
echo '<link rel="stylesheet" type="text/css" href="/static/css/default_day.css" />';
}
?>