When the class is fading, and the attention is just not there, it's time to pull out the Basketball.

This gains immediate attention.

1. Sound out loud a keyword for the day.
2. Throw to a student, have them repeat the keyword, and throw the ball back to you.
3.  Move to the next word, and repeat.
4.  Try to include everyone, by calling their name, and try to have them all repeat the keywords.
5. Once the keywords are familiar to them, then you can move towards defining them and related discussions.

Not only will they request to do this more often, they will spread the word to other teachers.

Variations - Pronounce the word and define.  If you can't define the word, pass the ball back to the next student.  This can be open book, because others will dilligently work towards finding the definitions before the ball makes its way to them.

Keep score by rows or groups, and have a reward ready for the best word group or row.  List all of their names and post them every day you use this activity.  This is a good Friday activity when attentions seem to wander to the weekend.