Sons of Gygax T-Shirt.
You know how fast She Who Shall Not Be Named would respond to such a shirt, which is why I suspect the window of availability is so limited. That being said, it could have been available for days and I was just the 6th person to buy a shirt. Somehow, I doubt that.
It would make a great Christmas gift but will not arrive in time for the holidays. You can, however, print out this blog post and stick it in an envelope and let them know what's coming ;)
edit - just to be clear, I'm just adding to the bandwidth - this is not something I'm involved with, except for buying a shirt myself :)
more edit - obvious link - https://www.gearbubble.com/gygax