I've seen most of their movies about a bazillion times each, and every time I rewatch one, I always catch a new pun or clever quip. I can't help but think we're a lot stupider (collectively) than we used to be because of television and the Hollywood blockbuster style of movies.
I have to admit that it takes me a second to catch what they just said and the joke with how they roll through it so quick and seamless. At least the play on words you get from Groucho and Chico. The slapstick of Harpo is pretty obvious.
Makes me wonder just how bad modern comedy has dumbed us down.