So how would one go about building one's own lightbox? I grew up in a sunny area, and can feel the effects of SAD. Having a lightbox to improve the mood would be helpful.
My recommendation is to go to Amazon, buy a 5 meter roll of bright white LED strip and a 6amp power supply (I found a replacement LCD monitor power supply for something like $11 and the LED strip for < $20). Cut the strip into segments and mount to particle board (perhaps with a picture frame in mind), making sure to stagger the position of the LEDs. If your board is non-conductive, you can mount thicker gauge stranded copper wire to either side of the board, and bridge the appropriate pin on the LEDA strip by soldering a short bit of wire to the power channel.
As far as electronics projects go, this one is pretty easy, and 5m of LED strip throws a lot of lux.