We're a little slow, so I thought I'd get the creative juices flowing.  Let's see what comes to YOUR minds.

I keep a NERF gun pen at my desk and pop project managers who invade my desk while I work.  Also used for popping co-workers in my immediate vicinity.  After sneak attacks, I simply switch it to pen mode and act like nothing happened (although it's rather obvious due to the bright, bulky orange tool).