How can PHP be used to include different files based on the time of day?

To include different files based on the time of day in PHP, you can use the `date()` function to get the current time and then use conditional statements to include the appropriate file based on the time. For example, you could include a "morning.php" file if the current time is before noon, and an "afternoon.php" file if the current time is after noon.

$current_time = date("H");

if ($current_time < 12) {
    include "morning.php";
} else {
    include "afternoon.php";
}