I'd never heard of it either, so I googled it. Here's an interesting site: http://blackgarlic.com/
Introducing a simple food with a wonderfully complex flavor. Black garlic is sweet meets savory, a perfect mix of molasses-like richness and tangy garlic undertones. It has a tender, almost jelly-like texture with a melt-in-your-mouth consistency similar to a soft dried fruit. Hard to believe, but true. It’s as delicious as it is unique.