I'm going to be honest. If you work with me, then it's likely you annoy me sometimes.
If you come to my desk, and I have my headphones in and I'm deep in thought writing some VB for a new database front end, then now is not the time to spend twenty minutes telling me every detail of your sinus infection.
I sit by the front door and have a weird social complex where I refuse to interrupt anyone for fear of being rude. Coincidentally, our receptionist Kay has this same complex. So we've worked out a secret signal system.
If one of us has been trapped for more than a few minutes, the other glances over to see if the Secret Office Signal (SOS) is being given. The sign has a few varieties - you can rub your head, tug on your ear, etc.
If you get the sign, then it's your responsibility to save your buddy. You may have to get creative with your assistance. Since your counterpart can't interrupt The Yapper, you have to do it for them by creating a diversion.
This can mean paging your buddy over the intercom, creating a fictional computer malfunction, staging a heart attack, etc. Whatever it takes.
You have to be careful not to get the signals mixed up, though. One time Kay tugged on her ear after brushing her shoulder, and I stole second by mistake.