Contact your local film school and ask if any students would like to film your wedding documentary style for a project.
You can still have your professional videographer there but sometimes new ideas or simply helping someone that gives you a little free video will be a nice touch.
Make a video of yourself thanking everyone who bought you something off the Wedding Gift Registry.
Make a treasure hunt for little kids that are coming, hide clues around the reception to kill the boredom that kids often experience at weddings.
By disposable cameras for the little kids to take photographs with.