Archeytpal "big dumb object" novel, and winner of the 1971 Hugo and Nebula awards.
The galaxy is exploding, from the centre outwards. Somewhere else will have to be found to live. The Ringworld might be the answer, so a group of characters set off to explore this big dumb object – an enormous, artificial construction ringing a star.
Despite Niven's background in hard science fiction, much of Ringworld maintains a wry sense of humour, with characters boasting tongue-in-cheek backstories and quirks.
The leader of the group, Nessus, hails from a race of two-headed herbivorous beings for whom cowardice is praiseworthy. Speaker-to-Animals is a huge, carnivorous cat-like creature, considered a weakling by his own race. Even the humans are odd; Teela Brown is congenitally lucky, and Louis Wu is 200 years old.
Peculiar alien races abound on the Ringworld, and the application of scientific principles eventually saves the day. The novel's world is built with Niven's typical intricacy and characteristic attention to big science and theoretical physics.
The novel was followed by three sequels. Several attempts have been made to film it. In 2001 James Cameron was the last Hollywood name rumoured to be attached, while in 2004 the Sci-Fi Channel announced plans for a mini-series.
Nominated by gregbordas and PlainclothesClown.