OK, so here's a series to watch if you have yet to see it. It's an American adaptation of a British series of the same name.  I am not always a fan of adaptations, but sometimes the adaptation is on par and even better than the British Original.  I like both versions, but the American version has more episodes available. British seasons only have 6 episodes per season, or 7 if there's a Christmas special, whereas the US season has 20 episodes per season.

Anyway, the premise in both shows is that a young couple inherits a large mansion, and associated land, which belonged to a dead relative that they are distantly related to. If the first episode the Sam (US)/Alison (UK) character who is the inheritor has a near death experience and she is now able to see the ghosts of people who have not moved on into the next phase of their after lives.  The mansion is full of them, and they span the centuries (cavemen, indians, soldiers, politicians, plague victims, etc.) -and they all have their personalities.  This is the first time they are also able to communicate with the living, so... hilarity ensues. Some characters are similar across both series, and some are unique to their locales (no caveman in the US, but there is a Viking ghost and a native ghost), and in the UK the beheaded ghost is a ghost who was a monarch who lost his head during a revolution, while the headless ghost in the US lost his head in a biking accident.

The US versions is still going, and the UK version just wrapped up (the series finale was one of the better ones I've seen) and with 73 episodes across both of them, it's quite a winter binger ;-)