Try a “FedEx Day”
This concept, popularized by author Daniel Pink, involves giving your employees free time to come up with something innovative that can be implemented in your business. Set aside a 24-hour period when employees can work on anything they choose. Make sure they have the tools and resources they need and impose just one rule: They must deliver something — a new idea, a better internal process, a service innovation or a new way to treat and interact with customers — by the following day (just as FedEx does). The results might amaze you.
SOURCE: Daniel Pink, from Drive: The Surprising Truth About What Motivates Us