Here's a wonderful mashup of existing technologies that promises to make it all but impossible for little kids to get shocked by a power outlet. The Guardian Angel Shockproof Safety Outlet uses similar technology as your smartphone's touchscreen to detect when it's being touched, and then automatically shut down power to eliminate the risk of electrical shock.
A pair of the replacement outlets is just $40, and installation doesn't require any kind of electrical or wiring know-how. You just remove the faceplate from an existing outlet, plug the Guardian Angel in, and then secure it with a set of screws. Unless your kids are good with tools there's no risk of them removing it, and the next time they try and jam something into the outlet it won't be one of those unfortunate 'learning the hard way' experiences. [Guardian Angel]