Its easier to keep a rolling log moving than it is to start a stationary log rolling. Once students are motivated, keep the momentum going by change, intrigue, surprise, reward...whatever it takes. This also spurs the instructor on to think of new creative approaches to keep themselves interested. Have the students expect the unexpected in a positive way. The urge to learn feels like the urgency to turn the pages in a really good book. Its best when they are salivating for the next peak at what is coming next. Then just as they think they have it all figured out - surprise them yet again. I am always on the search for new "positive surprise tactics" - any ideas would be greatly welcomed.