Silver duct tape gags are my absolute favorite. There is a great site,
tinychat.com/tapedmouths that I am trying really hard to promote. It's a webcam chat site where people go on cam with their mouths duct taped. It's a nice and fun site nobody seems to really know about. Let me know if any of you are interested in giving the place a try, I just might be willing to go on cam with you if so :).