Here's a block that you can use to do something on a particular day of the week (Monday, Tuesday, Wednesday, etc.). Can be easily adapted for other date intervals based on the php date function. Enjoy.

$day_of_week = date("l", mktime());

switch ($day_of_week) {
  case "Monday":
    //do whatever 
    print "<h2>Today is Monday</h2>";
    break;

  case "Tuesday":
    //do whatever 
    print "<h2>Today is Tuesday</h2>";
    break;   
   
  case "Wednesday":
    //do whatever 
    print "<h2>Today is Wednesday</h2>";
    break;   
   
  case "Thursday":
    //do whatever 
    print "<h2>Today is Thursday</h2>";
    break;   
   
  case "Friday":
    //do whatever 
    print "<h2>Today is Friday</h2>";
    break;   
   
  case "Saturday":
    //do whatever     
    print "<h2>Today is Saturday</h2>";
    break;   
   
  case "Sunday":
    //do whatever 
    print "<h2>Today is Sunday</h2>";
    break;   
}