Marvin: the grave jumper.
We had a grave popper (Marvin). A small skeleton sold at a local party store that had three or four audio comments. He was designed to use a push button or a light sensitive resistor to detect someone close to his face and then say something funny. I hacked the circuit board, added a transistor, and wired DC voltage back to a PICAxe carrier board. The PICAxe could control when he said something. I then built the lift mechanism with angel stock and pressure treated lumber. The lift arm was actuated by a pneumatic cylinder. A Passive Infrared sensor in a plywood gravestone detected movement and the PICAxe fired a relay to the solenoid valve and waited a few hundreds of a second and then fired the transistor to make the skeleton talk.