Jokes that are safe for work can either be about work itself or so clean that they couldn't offend anyone. An example of the latter asks what a pile of kittens is called. The answer is a "meowtain."
Jokes about work can sometimes be offensive. However, they can also be wry without offending people. For instance, one joke poses a situation in which a boss is interviewing accountants. The boss keeps interviewing until he finds an accountant who answers the question "What's 2 + 2?" with the answer, "Whatever you want it to be."
The Funniest Clean Jokes website has several jokes that are about the workplace yet are also safe for work. One example involves a truck driver thinking he can make it under a bridge but getting stuck. When a cop comes to write a ticket, the cop asks if the driver got stuck. The driver replies, "No, but I was delivering this bridge, and I ran out of gas."
The website Safe for Work Jokes collects jokes that it labels as "squeaky clean." The site includes a category for business jokes. An example of such jokes starts with a man arriving late for work. The boss yells that the man should have been there at 8:30. The man asks, "Why? What happened at 8:30?"