Some years ago I coded an answering machine based on a voice modem. With it, any number that was not on my list of “friends, relatives, or businesses”, went into the game. The game consisted of a series of questions by a robotic voice which required a key pad response. Anyone willing to play the game finally ended up with a reply of “Invalid response. Goodbye.”. I used mgetty, festival, and a few minor pearl scripts to interface with an old US Robotics voice modem. Worked like a jewel once the bugs were out. My new computer doesn't have a serial interface so that answering system is on a shelf for now. But, it was fun to sit back and see if anybody wanted to play.