I made this script in ten minutes for fun. It uses GDLib to create an image telling you if it is the day you asked for.

Usage:
http://yoursite.com/dayofweek.php?day=monday
This will tell you if it is monday or not. Works for EVERY single day of the week!

Examples:

Sunday:


Monday:


Tuesday:


Wednesday:


Thursday:


Friday:


Saturday:


On Error (no date set):


C0d:
PHP Code:
<?php
Header
"Content-type: image/png");
$day strtolower($_GET['day']);
switch (
$day) {
    case 
"sunday":
        
$printday "Sunday";
        break;
    case 
"monday":
        
$printday "Monday";
        break;
    case 
"tuesday":
        
$printday "Tuesday";
        break;
    case 
"wednesday":
        
$printday "Wenesday";
        break;
    case 
"thursday":
        
$printday "Thursday";
        break;
    case 
"friday":
        
$printday "Friday";
        break;
    case 
"saturday":
        
$printday "Saturday";
        break;
    default:
        
$printday "FAIL!";
        break;
}
$image imagecreate(100,18);
if (
$printday!='FAIL!') {
    if (
date('l')==$printday) {
        
$color ImageColorAllocate($image,0,255,0);
    } else {
        
$color ImageColorAllocate($image,255,0,0);
    }
    
$black ImageColorAllocate($image,0,0,0);
    
ImageFilledRectangle($image,0,0,320,130,$color);
    
ImageString($image1220"$printday"$black);
    
ImagePNG($image);
    
ImageDestroy($image);
} else {
    
$color ImageColorAllocate($image,0,0,255);
    
$black ImageColorAllocate($image,0,0,0);
    
ImageFilledRectangle($image,0,0,320,130,$color);
    
ImageString($image1220"You suck!"$black);
    
ImagePNG($image);
    
ImageDestroy($image);
}
?>