My employer, Google, has an internal website which allows you to view a photo of every employee by looking up their name. It is an awesome feature, especially as a "Noogler" (the name for a new employee).
Each employee uploads the photo of their choice. Today, April 1st, when you look up any employee, their picture has been superimposed with either a handlebar mustache or a pair of rhinestone sunglasses, layered onto their face. The gag appears in every single employee photo...perfectly positioned. That is some brilliant software programming.
Happy April Fool's!