How to set up a fake phone number

I learned about a phone service called Twilio from reading this Lifehacker article. The article is mainly about how to set up a phone number that makes calls 'disappear into the ether, never reaching me, never bouncing back, but disappearing like a stone tossed into the fog.' I'm not sure why just making up a random number wouldn't be the easiest thing to do if that's your goal, but Twilio sounds useful if you need a way to receive voicemail from certain people without having to hear your regular phone ring. One cool thing about Twilio is the way you can create a computer-voice announcement just by writing the words you want it to say:

But here’s the fun part. When you click on your phone number’s settings on the Twilio dashboard, you can tell the service what it should do when somebody calls or texts the number. By default, it reads a little message (saying that you haven’t set up the number, or something). So I copied that message, and altered it so it sounded like a full voicemail box. Here’s my script:
You have reached. 5 5 5. 5 5 5. 1 2 1 2. Please leave a message after the tone. This mailbox is full.
Image: By takayuki/Shutterstock