So what do you do when Nightbane is giving your guild a nightmare? My personal preference is to tackle some content you can handle, whether that be running through the old world raids just for fun, or, more likely, trying to take down some of the overworld bosses. Of course, if you're stuck on Midnight and Attumen, there's not much more raid content to go back to seriously. But if you're having trouble on a boss that early, odds are you need better gear anyway -- wipe on Attumen a few times, and then split the raid into groups and go run some heroics. Always have an extra option planned for your raids, too, because there's no need to bang your head on a boss you can't beat -- even if you just wipe on Gruul once, you've gotten that experience. Then take your raid back to Karazhan for more practice and more gear. Eventually you'll hit a point where people want to keep trying (because you'll be so close), and then guild progression is on.
But while that's a solid tactic, it's not the only one -- I've seen guild leaders run social activities, declare "bounties" on bosses or instances, and even offer to pay repairs just to try a raid boss out for a night. How do you bring a guild that's lost its game back into the raiding gauntlet?