Larry Niven's early writing is notable for his characters' witty dialogue and narration even in the face of mortal danger. His Crowning Moment of Funny from this period is the banter between Beowulf Shaeffer and Elephant in "Flatlander". However, in the 1980s, after The Ringworld Engineers, Cerebus Syndrome seemed to have set into Niven's style and it never quite recovered.
Beowulf Schaeffer: "How about that, Elephant! Our hull's evaporated!"
Among the Man-Kzin Wars stories, the only one intentionally written as a comedy is "String" by Hal Colebatch and Matthew Joseph Harrington, in volume XII. It even has a Shout-Out to Girl Genius of all things.