if you are in inferno and want to kill any of the bosses heres how you do it

join a game at the current highest difficulty you have and the difficulty you wish to complete the new glitch quest in
leave game
join a friends game at lower difficulty but at this quest you wish to complete(example diablo)
leave game
resume game=your in inferno diablo

just a lil tip for those inferno item hunters ;P help me lower these dumb auction house prices of blues