How to Keep Students Engaged in Class

I just read an interesting article called How to Keep Students Engaged in Class. It was a good article. Though I surely wouldn't try all the things it mentions in the course of one class period. But it is good to have several tactics to use.
One tactic I do use everyday is switching up activities frequently.  For example, the structure of every English class period looks like this:

• Silent Reading
• Writing in Journals
• Additional Instruction/ New Information
• Practice

My Spanish classes also follow a structure:

• Self-directed Review for Previous Day/ Anticipation activity
• Speaking Exercise  (Usually takes the longest.  Students speak, I correct, and have them speak again in partners until I feel they have the concept.)
• Class discussion/Instruction
• Review of Day (Sometimes a review game)

In the beginning of my teaching I thought a daily structure would make the class boring, now I think it provides sanity.  Students perform better if they know what is expected.  They feel safer, and less time is spent giving instructions.  Also, the variety of activities that can be done within the structure helps eliminate boredom.

But I think the importance of structure was really highlighted when a sub was supposed to come to class and didn't show up until late.  I was in the school attending a meeting and was called out to watch my class until the sub showed.  When I walked in 34 of my 36 students were on task and working.  The two that weren't on task were asleep.  (It's a lot better than some of the alternatives.)