I'm using this for a job, and I don't think I need it anymore - but I don't want to throw it out just yet either. Today is 12 Jul 2013, so in a few months if I haven't used it I can throw this out.

getWeekEndpoints

/**
 * Takes a date and calculates the start and end of the calendar week that it's in.
 * Start will be 00:00:00 of the Monday of that calendar week, and end will be
 * 00:00:00 of the Monday of the next calendar week (ie, just after the Sunday ends)
 *
 * @param  string $date MySQL friendly date, with format "Y-m-d H:i:s"
 * @return array - has two keys, 'start' and 'end' which are the boundaries of the calendar
 * week, in MySQL format - ie, "Y-m-d H:i:s"
 */
  protected function _getWeekEndpoints($date){
		$timestamp = strtotime($date);
		if(date('D', $timestamp) == 'Mon'){
			$startTimestamp = $timestamp;
		} else {
			$startTimestamp = strtotime('last monday', $timestamp);
		}
		$weekStart = date($this->sqlDateTimeFormat, $startTimestamp);
		$endTimestamp = strtotime('next monday', $timestamp);
		$weekEnd = date($this->sqlDateTimeFormat, $endTimestamp);
		return array('start' => $weekStart, 'end' => $weekEnd);
	}