It is indeed the entire 660 card 2011 Topps set, Diamond Anniversary Edition! I'm not quite sure if I ever did complete the set myself, but even if I did, this is still pretty awesome. I happened to dig this up as a prize in the Diamond Dig feature. Besides unlocking various virtual rings, this was without a doubt the best thing that's happened to me on one of these online sites Topps has had the past two years. I doubt I'll open it anytime soon, if ever, because I know what the cards look like. For not a single penny, I was able to add a $50 set to my collection. Not too shabby!
Any of you other guys get lucky on the Topps giveaway sites? See Ya!