This began as one of those challenges to self constructions. The answers rather obscure and at first I figured nobody (but Mikey G and Benchen) could possibly get it. But when I wrestled with how to do it, I think I included enough clues to figure out what to do (albeit why might be another issue). When you get the solution try and Google to see if it makes sense. It's fairly interesting (for specific values of interesting).
Anyway, think inside the box.
(BTW, the grid was surprisingly hard to fill)