SIERRA NEVADA BREWING
They are the second largest craft brewer in the US (behind Samuel Adams / Boston Beer Company), the seventh largest brewer overall, and you haven't heard of them?
As TroyTempest asked, with what beers are you familiar? I see you have a lot of Hawaii posts, so if you do live there you may have some serious gaps due to the limited distribution there.
I don't think their brewery warrants a special trip, unless you are in Chico for whatever reason.
Overall I would rate SN as a great brewer, but would say that they have quite a few offerings and at least to my palate I find that there's a fairly wide dispersion in the brews that I really like, and really don't like.
Interesting you put up this post as I was just going to (and will) post on a couple new SNs I tried a few days ago: Flipside "Red IPA" and Narwahl Imperial stout... true to form I loved the Narwahl and didn't care much for flipside.