Get drunk.
Keep paper and pen handy.
When you feel the buzz coming, let your mind wander.
As soon as you can, write down thoughts. Just thoughts, not sentences. (they tend to travel upward off the line and then the page, trust me)
You may surprise yourself and become Hemmingway style writer.
Always do sober what you said you'd do drunk. That'll teach you to keep your mouth shut.
It was a good idea. Then it rained. He died.
*shudder*
(With apologies to Hemingway's Ghost...)