I get what you're saying - Doonesbury is maybe a good example of one that you really had to be there. On the other hand a lot of the classics that do have a tim

I get what you're saying - Doonesbury is maybe a good example of one that you really had to be there. On the other hand a lot of the classics that do have a time based cultural context can still be very funny. Take Asterix where a lot of characters wore the faces of contemporary celebrities or politicians, but that was a secondary joke so they still maintain their appeal. The Simpsons and South Park also have a lot of cultural references but the early seasons are every bit as funny now. Classics like Marge vs the Monorail still hold up as the core theme is one that keeps repeating every generation, but a guest appearance by Leonard Nimoy wont mean anything to a new audience.