Classroom Culture

So, I’m only two classes away from completing my teaching requirements for this internship.  One thing I’ve noticed after teaching several sessions is that, while you may teach the class the EXACT same way every time, sometimes the “classroom culture” is just not going to play out in your favor.   At this point, I feel like I have a pretty decent grasp on the BCE/New 222 classes, but no two classes are the same.  Sometimes I have a super class that loves to participate and, at other times, I have a dud of a class.  I mean, just a DUD.  More than anything, I find that if the instructor does not promote a lively/interactive classroom during a typical class period, there is going to be little hope of getting participation out of the students in a library session…and that is a tough nut to swallow.  I have a real yearning to make every class THE MOST INFORMATIONAL AND FUN CLASS OF ALL TIME, but often times my own enthusiasm is eclipsed by poor classroom culture.  And while I think we should all strive to overcome such things, sometimes you just can’t seem to get around it, and that is frustrating.  Has anyone else come across this?  Do you have any suggestions for encouraging apathetic students?