Using cartoons can be a great way to engage your students in grammar concepts. First, you can create the comics or you can have them create them in the computer lab. This would be a great project to let students process the grammar and contextualize it. ToonDoo is an excellent website that lets you have free access to making cartoons for your class. It is worth your time and can be an effective way to add variety to your teaching.
Here is an example:
Here is a short book that I made: http://www.toondoo.com//ViewBook.toon?bookid=584856
I think students would enjoy this.