Not a new idea - but just a reminder to use pop songs in the language learning classroom.  Songs introduce great vocabulary - which can be chosen based on a particular theme - cover modern slang, and bring up speaking points.  Take care when choosing for all school children, and high school students, as many songs may not be appropriate.  Adult students are open to many kinds of songs and the best idea is to bring in something fairly modern to accommodate all the learners.
A list of themed songs can be found in my essay on pop songs.  Many ideas on can be found on the Internet. 

If any readers have more ideas, please send some suggestions in the comments section.

An excellent, (self-tested) way of testing your students - and having them really learn well - is to divide the grammar they have studied into small sections and give each student a part that they have to present and teach to the class on presentation/test day.  For example, one student will get the present perfect, another the present perfect progressive(continuous), - covering all the parts that were in the curriculum.

This means that each student works on a presentation for his/her grammar section.  On the day of the presentations, all the students get to see presentations on all the grammar structures that were learned that term.  I have found that this system really gets the students to work and truly understand their grammar part, and by seeing other students explaining their part, helps them to absorb the material presented in another way from the teacher's style.    The teacher can also tell the students after the presentations that if they have a particular problem with one of the structures, they can ask the student who presented that part, for help.

Try it out and send some comments.

Creative fun can be used for grammar practice.  Not only games but also creative writing can be used for grammar structure practice. 
Write a dialog with the new grammar structure and use it for some practice, and then get the students to do the same.

Acting our the scenes will enable all the students to enjoy their own work presented, and each pair of students get to act out two scenes. An excellent source for original work (written by the students) and fun in the classroom for all.
This website has a whole menu of grammar dialogs, so please take a look.