Cascade Brewing has got to be the king of American non-Brettanomyces sour beers. They are quite purposefully a Lacto Lab (that's a cool new phrase I just coined that we are all going to use now).
Every Tuesday you can come see some blinkin' amateurs tap a new keg. Maybe those blinkin' amateurs can even be you. http://www.cascadebrewingbarrelhouse.com/tuesday_tappers.asp
Or you can just come drink the beer.
5:45 Arrive for the last 15 mins of Happy Hour for $1 off an imperial pint.