Here's a couple of ideas for ya... You could put a TV in a window running one of those "fire" fx videos. Make a black stencil to cover the whole front of the tv but cut out a 666 in the center of the tv so the fire shows through the numbers.
Or, if you know somebody who can do CGI animation for you, maybe you could get them to create a flaming 666 effect. Burn that to DVD and run it on a tv as-is.
Or, if you know somebody who can do CGI animation for you, maybe you could get them to create a flaming 666 effect. Burn that to DVD and run it on a tv as-is.