Here's a thought...if you need to put your cell phone ringer on loud enough to be heard across the office, how about you actually ANSWER IT instead of letting it ring its obnoxious ring tone all the way through for 30 seconds?
Or better yet, turn it the fuck down before people go DEAF IN WYOMING.
Try this. Next time it's going off, if you can get to the cell phone with a glass of water before the person comes to answer it, then I think you are more than justified in dropping the offensive phone into the cup.