Alright, we'll go with the possessed modem. I was the fool in this story…no one ever believes that I was an innocent victim, though (including the phone company) but I maintain my innocence to the bitter end:
I was setting up a new computer in my home office, and I am very meticulous about it. I uninstall everything I never use and automate all the tasks I perform frequently. One of the things I do often is email files to myself, like my phone list for example. I also had a spiffy new email client that did everything but wash the dishes (I have uninstalled it now and buried the disk in the back yard, but back to the story.) So I set up my email client to page through messages at the touch of the arrow keys, and it also launches or views any attachments (like the phone list I mentioned earlier) automatically in another window.
I also have my modem set up to dial without prompting, (this is back when I had dial in internet) because it saved a step or two when launching my browser and seemed convenient at the time. There were a couple other little technical details, but this part gets boring…
Now, I get spammed like everyone else; but it is usually just a question of deleting the offending posts, and at the time I wasn't using any fancy blockers etc. So I am paging through the my mail, and I start seeing the spam ('are you horny' or some such.) Intriguing, but send to trash. Trash. Trash. What's that strange clicking sound? This is no ordinary spam… The spam had attachments, and the attachments were executables, and the executables were dialing my phone! So I change all the settings and throw out the dangerous programs, and don't think about it again…until my phone bill arrives.
Waverly: "Hello, customer service? There are incorrect charges on my bill."
The young, attractive sounding woman on the other end pulls up the info on her screen
Woman: "Which charges, Sir?"
Waverly: "These international ones, the only international calls I make are to the UK, and these are different"
Woman: "The International sex-phone calls?"
Waverly: "Yeah, maybe, but I didn't make them"
Woman: "You didn't make the SEX calls that are on your bill"
Waverly: "No, I think my modem did it…"

Woman : "Hmm, I see…."
There is very little embellishment here. Go ahead make your sick jokes, but as I said before: Waverly es inocente!