Abstract: An interlocking toy building block has a block body, projector assembly and film. The block is formed within interconnecting building elements thereon for connection with other toy blocks, and a projector opening is defined in a side of the block body. The projector assembly includes a lens arranged in the projector opening, a light source arranged in the block body to direct light outside the block body through the lens and projector opening, and a power assembly supplying electrical power to the light source. The film having an image thereon, the film arranged in the block body between the light source and the lens, such that the image on the film is projected externally from the projector opening by the light from the light source passing through the film and the lens. The film can be in a removable cartridge and the lens can be included in a focusable assembly.