Even though great-great-grandpa Colonel Unplggd really loved his Hot Pockets, we doubt he was to blame for an unattended toaster oven powering on. Instead, it looks like it's just a case of faulty electronics. Many different small appliances have been reported to mysteriously turn themselves on due to faulty electronics, as Consumer Reports explains:
The problem was cited in at least 10 toaster oven recalls issued between 2005 and 2009. Last week, 122,000 Frigidaire and Electrolux cooktops and ranges were recalled because they unexpectedly turned themselves on. In this case it was from liquid pooling under the control knob. We’ve also heard reports of a Magic Chef range that was inadvertently turned on and off by the wireless signals from a nearby cell phone.
Even if you've never experienced anything like this, you can use the tale as a lesson in safety. Always unplug your counter top appliances when they're not being used. And if it ever does happen to you, Google your appliances make and model number to see if it's been involved in a recall. In either event, contact the manufacturer and let them know about this possible defect—you might be the first one to get a visit from the coffee maker ghosts.
(Toaster oven image: Flickr user MwaO under license from Creative Commons, toaster image: Flickr user Sidereal under license from Creative Commons)