Quoted from bbriese:

I did a Gorgar project a few years ago for a buddy and made a spare backglass. So last year I wondered what to do with it....decided to slot some 1x2 to hold the glass around the edge, painted it white, backed the shadow box with some silver foam insulation board from home depot and glued LED christmas lights in the right spots then screwed the whole thing together. Came out awesome.