The answer to the joke "Why couldn't the chicken find her egg?" is "Because she mislaid them." The joke makes a pun on the word "lay," as in a chicken laying eggs, by adding the prefix "mis-" to it. Mislay means "to lose temporarily."
"Knock, knock." "Who's there?" "Opportunity." "Don't be silly. Opportunity doesn't knock twice!" There is the opportunity, however, to take classes and workshops to learn to be funny. Additionally, there are other resources, such as social media, that may provide some clues for improving humorousness.
While each workplace may have its own culture and set of rules regarding pranks, there are some pranks, such as cubicle decorating, that are less mean spirited than others. These nicer pranks might not lead to formal disciplinary action.