I remember way back when raiding Zul'Gurub, the spider boss would cause people to get drunk, blur up their screen, and make it hard to see during the raid.
The way to get around this was by turning off Full Screen Glow Effects in the Video Options.
Now granted this may be a Repost, Common Sense, or Old as The Internet, but I feel it deserves a bit of a reminder as I know a few people who could use this information with Brewfest. Like when the Dark Irons attack brewfest, and you get drunk. Simply turn off Full Screen Glow Effects and you can see clearly...
-- Kudu