I am a geocacher. I was reading a book the other day that mentioned a phone number in it and not being a 555 number, I called it for the hell of it. Surprise! It was purporting to be the person named in the book.
I got the idea that this would be a great way to give a clue to a puzzle or multi geocache. Does anyone know of a free service where I could leave a message that could be picked up by calling it on the phone?
You could try Google Voice. You have to request an invitation, but I got mine in a week or two. Afterward, you get a free phone number and you can record a custom greeting… at least in theory (I’ve been having some issues with that feature, but maybe I’m just doing something wrong).
ETA: As an added bonus, the service records caller ID and even transcribes voicemail to text for you. With some fancy scripting, AI, and text-to-speech, you could even arrange to have a creepy call-back a few hours later… almost like that contorted-realities spy-game Majestic.