Our school encourages teachers to obtain at least 1 outside lecturer per term in our concentration. I have been teaching onsite for over a year and just couldn't seem to find the right person. I didn't give up though and last month stumbled across a motivational speaker that owes some of the school management some "favors". I'm actually getting a periodic lecture for free. Additionally, as far as I'm concerned, she ranks high on my list of really good speakers. My point here is - keep looking. These folks will break up your class and add energy to the students.