Three years ago, Stone Brewing wrote a post on their company blog titled "MustardGate 2010" in which they announced that the Stone Brewing mustard they've been shipping to their customers was missing an important ingredient - their beer. As it turned out, the company they hired to make the mustard for them never used the beer Stone sent them to make the product. The kegs Stone sent them came back empty, so there was no clue where the beer actually went.
I admired Stone for being this forthcoming, and for going out of their way to make things right with their customers and their fans by offering refunds, discounts, whatever it took to make things right. But in the end, it gave me the inspiration to make that mustard myself. I'd made mustard before, and beer makes everything better. So I made it, and it was delicious, especially when slathered on Bratwurst or (in this case) smothered on beer-braised corn beef & cabbage.