Note: This works on all live servers
When i bought the brewfest "Beer of the Month". You get this mailed if you got a club membership during the brewfest. I noticed that they don't disappear when they are drunk, but still create empty bottles.
And now the big point: You can sell the empty bottles for ~50 copper per 24 stack. This is quite nothing, but remember that you can produce endless stacks of them. Use this exploit as fast as possible, i think it will soon be fixed!
Tips: Go somewhere to a vendor, where nobody observes you. Maybe you just wont somebody to see you endless drinking, with an army of squirrels around you.
Update 10/16/08: Works.