Risk it all for the big prize
Generally, when a roleplaying character is stuck in a rut, it's due to one or two plots that have become both unresolvable and impossible to ignore. If your character is trying to make a breakthrough in alchemical technique but can't do so until the next patch comes around, for instance, you have to be pursuing the goal in-character but know that it's not going anywhere out-of-character. There's no plausible reason for him to leave the goal to one side and no actual development to be made.
So the solution becomes easy enough: Give him something far more important to pursue for the time being, something that provides a strong enough motivation that he has to put other projects on hold to chase after something far more significant.
Sometimes, this can be an external development that he simply alludes to in a quick remark -- he has to spend less time in the lab and more time defending against the orcish incursions from the north, for instance. Other times, you can go ahead and offer up a big, longstanding character goal. If he's spent years searching for the man who killed his father, suddenly placing that man in front of him will be more than enough of a draw. All he really needs is a compelling reason to move his previous projects to the back burner.
The bright side is that if you're in a temporary rut, this will knock you out of it for a bit, and hopefully you can keep moving afterward. However, sometimes you're going to find yourself in a more long-term character rut, which won't be fixed by this plan so much as briefly forestalled. There's also the minor issue that you can't solve every problem by introducing a new character goal to chase, or else it starts becoming a variant on the Knight Boat problem.
We haven't met, but I need new friends
A steady roleplaying group leads to many advantages and some distinct disadvantages partly because you will often find yourself surrounded by a group of characters that play to your character in a certain way. Maybe she's stuck in the middle of a romance triangle that's reached the status of full-on plot tumor, with neither of her options capturing her attention enough for any sort of forward momentum.
The solution, again, is pretty obvious. What do you do when one group of friends has become inundated with drama? You spend more time with the other group.
I'm not saying by any means that you should leave your regular group behind forever. But if your character is becoming stagnant in a given setting, logic would dictate that the best option is to get her out of that setting and out of the same behaviors she's been performing for a while. It gives her a chance to make some larger changes, get some different perspectives, and come back with a renewed focus on moving things forward. Even if you don't switch to an entirely different group of people, you can certainly spend some time away from the people you usually associate with, just to get out of the same routine.
Aside from the verisimilitude, this is a great way of getting out of a rut that's stuck due to character interactions. It makes perfect sense and fits into normal behavior seamlessly. On the other hand... well, even leaving aside that not all ruts are based off of stagnant character interactions, there's the fact that you have to leave familiar waters for it to work, not to mention that telling your regular roleplaying buddies that they're boring you with stagnant interaction may not produce quite the long-term good feelings you'd like.
I'm actually the evil twin of your evil twin!
Sometimes, the problem isn't so much the situation as it is the character in question. It turns out that he or she just doesn't produce the interesting interactions you were hoping for, and so you're left to twist in the wind... or more reasonably, you start doing a bit of reworking to kick the character into a more interesting place.
This is the last option for two reasons. The first is that you're going to be making a big change to a character that may or may not work out any better in the long run, so it's sort of a final effort rather than an initial one. The other reason is... well, I already talked about this a while back. (Yes, I'm going to have to start referencing back more and more as I'm hitting the two-year mark.) So it deserves a whole column, but it's already gotten one.
And now nothing will ever go wrong again ever forever
Getting stuck in a rut isn't good, but you can get out of it. The tricky part is avoiding the rut in the first place -- and that's a topic for another week.
As always, let me know what you think of the column in the comments below or via mail to firstname.lastname@example.org. Next time around, I'm going to touch upon an issue that's currently dear to my heart. How do you make a tragic or sad character work over a long period of time without getting unpleasant to play?
Every Friday, Eliot Lefebvre fills a column up with excellent advice on investing money, writing award-winning novels, and being elected to public office. Then he removes all of that, and you're left with Storyboard, which focuses on roleplaying in MMOs. It won't help you get elected, but it will help you pretend you did.