In SL I could choose a animated/or not, texture that would project either as a static colour and or a texture from a polygon face to nearby polygons, depending on the projections range, lumienciance and projection trapezoid.
I would use this technique to project animated flames textures onto nearby surfaces, fireplace walls, ceilings and wood for example.
I would also use this for projected stained glass light into a room, which would not interfere with dynamic shadows.
Another use, water fresnels and caustics. Flickering candle light, the list goes on.