For the calendar at the bottom of the page there are two options:

(1) Switch to using the simple trailer by setting in your config file:

$simple_trailer = true;

or, (2) eliminate it completely by adding the following rule to a custom CSS file (see systemdefaults.inc.php for details of how to set one up):

div.trailer {
  display: none;
}

To just have the current month in the mini calendars above the table, add the following to your custom CSS file:

#cal_last, #cal_next {
  display: none;
}