Osho used to spice his talks with many jokes. In the seventies, these were often jokes of "Mulla Nasruddin", a cultural phenomenon in India.
From 1971 to 1975, four bundles of these jokes were published. These were all handwritten by Osho himself, then printed (source: Sw Yoga Chinmaya, personal communication). Only Thus Spake Mulla Nasrudin is printed purely as facsimile of Osho's handwriting. Around this time, there were several other joke-book-titles mentioned (included below), but never published.
The 688-page Take It Really Seriously (1998) is a compilation of many of the later jokes told by Osho in his discourses.