Are there any known ways to treat an acute gout attack without medication?

Ice. Cool that joint down with an ice pack. Cherry juice may help but is expensive. Colchicine, a common gout medication, is actually derived from the root of a plant, the autumnn crocus. Other dietary changes that may prevent flares include vitamin c, and low-fat dairy foods.
Nonfat powdered milk. Just published this week in the annals of rheumatic disease is an article describing two servings of enriched nonfat powdered milk mixed in a shake decreased the flares of a gout attack.
Plant lithium. Lithium from plant sources - lentils, broad beans and peas helps with gout available as li-zyme by biotics.