The Oldest Beer Recipe in History from Ancient Sumeria, 1800 B.C
openculture.com
openculture.com
I translated this recipe back while I was in school! Lots of fun.
(Though I'm more of a scotch ale man myself)
And then there's IPAs, which have triple that.
They're a weird fad right now and, while I enjoy the odd IPA, there's more to the beer world than hops!
My theory is craft breweries realized that they could take a mediocre ale, dry hop the crap out of it, and then charge a premium for the result. ;)
I think that the explosion in choices, availability, and quality have been great for consumers, American manufacturing, and the community that these breweries build around themselves.
[full disclosure: I work in the beer industry)