Print the model, take your mobile phone and turn the flash on, place model over flash.

It's one way to get noticed in a pub anyway :).

You can try alternatives like having the flash send a morse code message (as provided by the Android FlashLight app) or use alternative light sources (a torch should work well).

As shown in the picture, using a small/translucent print between the gnome and the flash changes the colour (my gnome was printed with ABS natural at 10% fill - it might give better results when playing with this). I tried with a black print, and light mostly comes out through the eyes.