I'll start with two people from Charmed that have something in common.The following person says a fact that my second person and someone else from Charmed have in common.

Example:

Alyssa Milano and Brian Krause acted in Charmed.

Than the next person says:
Brian Krause and Shannen Doherty both have green eyes.

So the next person has to say something that Shannen Doherty and someone else that had to do something with Charmed(actors, characters,guest stars...)have in common :)