I am not the discovery channel

Next week I am giving a seminar at a primarily undergraduate institution. After accepting the invitation I was told that I should plan on giving a "data light" talk that should be geared toward a sophomore-level understanding. At the time, I thought no problem. Now that I am putting the thing together I realize that it's a complete pain in the ass. Rather than be able to borrow heavily from a talk I had already put together, I have to build one almost from scratch. Added to that is the problem of giving a general talk on a single concept that is 50 minutes long without it feeling like a class. That isn't a problem when you can go into depth on a particular question and present data, but without that you are left having to broaden out the topic and present lots of examples of a concept without delving in to the nitty gritty. Maybe this will be good for me, but that isn't exactly a motivating factor right now. I know things are bad when I procrastinate putting a talk together by doing a review on a paper with all foreign authors who decided that they didn't need a native english speaker to deal with their grammar before they sent the paper in.