And in Ankh Morpork, there's the hoho: A cunningly designed ditch like a Haha, only the Hoho is 50 feet deep. Has claimed three Palace gardeners. Also once trapped Dr. Cruces, then head of the Assassins' Guild.
Interestingly, if this is accurate, it means that the front/backness of the vowel in hehe/haha/hoho correlates with its size.
God I miss Pratchett's satire.