Custom PHP Conditions? | WordPress.org

Is there any way to write custom PHP conditions? I’m a code/PHP hack, so a simple example would be good if you have anything. Something like:

<?php
if ( my_custom_function === true ) {
   return false; // Block is Hidden
}
?>

A different plugin, Wicked Block Conditions has a feature to “Show or hide blocks based on the result of a PHP function.” I may end up using it, but wanted to check and see if you had something similar.

Thanks!