One of the more popular functions in PHP is strtotime. Occassionally I see it paired with date to find out a month or day. This is inefficient compared to using today's function - date_parse

Date parse returns an array about the date, or false if the date is invalid. As of PHP 5.4 you'll be able to use array offsets on the return to grab the month, day or year immediately

Code php:
// Example of offset access available as of PHP 5.4
$day = date_parse('2011-03-04')['day'];