DEMO is a file extension that is used by a program called VirtuaGirl. It is a free, entertainment-only application that displays dancing, skimpy girls (e.g. in bathing suits) on the desktop of the operating system. It is a kind of program - a gadget intended for adult users.

DEMO are files used by the program to store video material which is a demonstration of the selected dancer in the program. This solution is aimed at a quick preview of a given model without the need for selection and approval in the program. There are many such files preinstalled in the application.