There's also a science career opportunity to bring an urn or gravestone to work and have it restored.
I've done it 3 times, and it said the experiment failed, but it turns the urn\stone into a playable ghost.

I'll kill some more of my neighbors and see if it ever succeeds. 
After you accept the opportunity and bring in the first stone\urn, an option for "restore ghost" appears on the science bldg.

personally, I like it when you're riding your bike and cars just run you over from behind and then *pop* there you are again at the back of the car, still pedaling away like the car was just a piece of scenery animation...oh wait!  It was.