All this talk about the Grey's Anatomy/Private Practice crossover event (which ends this week) has got us at TWoP thinking: true television crossovers are rare. They are not merely spin-offs (though they often involve characters from a spin-off), and they require more than just a mere mention of something from one show on another -- actual characters from both realities must interact. For ease in production, crossovers often happen between shows on the same network -- usually between shows from the same creator -- but occasionally they occur between shows that have seemingly nothing to do with each other. So what are the best examples of this elusive and mysterious breed of television event? Here are seven that we feel stand out from the annals of character-jumping television history.
1) "The Simpsons," Lisa Simpson-- Lisa's convictions are strongly leftist. She is a vegetarian and has expressed a desire to become a vegan. Lisa also joined the animal rights group PETA.
2) "Friends," Phoebe Buffay -- Portrayed by Lisa Kudrow, Phoebe is somewhat of a champion of animal rights and the environment. She is a vegetarian and doesn't eat "food with a face. She is against the wearing of fur coats, and cries when flowers die.
3) "Green Acres," Oliver Wendell Douglas -- Oliver was a New York City attorney who had a dream of moving to the Midwest and operating a farm rather than practicing law. He didn't adjust well to farm life, not for lacking of trying though. The show concentrated on farming, growing your own crops, and caring for animals.
4) "All in the Family," Gloria and Michael Stivic -- Portrayed by Sally Struthers and Rob Reiner, they shared liberal political beliefs. An example of this is when Michael got arrested for a nude protest at a nuclear power plant.
5) "Ellen DeGeneres Show," Ellen -- Ellen is a big animal activist and lover of the environment. On her show she often refers to the hybrid car she drives and tries to get as many pets adopted as possible.