The Duke Lemur Center, on the Duke Forest land north-west of campus, is a working primate research centre that opens to the public for guided tours by advance booking. You see lemurs at close range — sifakas leaping between trees in the warmer months, ring-tailed lemurs sunning themselves, the strange aye-aye lurking in its nocturnal house — in a setting much closer to the rainforest than a zoo.
Tours run several times a day Tuesday through Saturday and book up weeks ahead in peak summer. Allow about an hour for the standard tour; longer specialist tours go behind the scenes. It is not cheap by Durham standards, but it is the kind of experience that genuinely justifies the price.