The problem of writers' block has been mentioned a handful of times in the comments over the past several months, and I recall at one point being asked (via Twitter, if memory serves) to offer possible remedies/solutions, rather than simply saying that writers can't afford to suffer from it. So: here goes.
First, I'm not sure I believe in writers' block. I certainly believe in writers' laziness, since I've suffered from it a number of times, but I don't think I've ever had any dry spells that I couldn't write my way out of with a little discipline and a few tricks. My favorite trick is automatic writing.
Now, the Wikipedia article on the topic makes the whole thing sound a little mystical and—well, crazy—so let me clarify: when I say "automatic writing," I mean writing without any interruption or editing. No pausing to think, no re-reading what you wrote, no need to pay attention to anything except the next word. (No trances, &c, at least not for me.) Sometimes you end up writing things that don't make any sense. Sometimes you end up writing "I can't think of anything to write" twenty times in a row. The point is, however, that you're writing—and while the product itself generally isn't even close to first-draft quality, I've found that there are usually a few brilliant nuggets that jump-start the more usual, conscious, craft- and plot-oriented writing.
So, if you find yourself stuck in your writing, set aside twenty minutes a day to write without your internal editor looking over your shoulder. Will it be good? Probably not—at least, not most of it. But you'll be writing, you'll be reinforcing good habits and providing structure for your writing life, and you'll almost certainly discover one or two great ideas buried in your subconscious that you might not have had any clue you'd produced.