Writer's block = story of my life.
Well, all right, it hasn't always been so, but it's something I've got used to over the years. I haven't been able to write a long, fully-developed story in over two years, because every time I try I hit writer's block at one point or another.
The solutions that the other suggested are great to go through lack of ideas. I'm particularly fond of brainstorming. What's harder to fight is when you know where you want to go, you know how you want to get there, but you can't get the words onto the screen. Then, there's something I've experienced which works really well: get your BR to write a couple of lines for you, to get you started again. It helps in a tremendous manner.
What I haven't managed to fight fully yet is lack of enthusiasm for writing. Brainstorming is still the best solution as far as I've experienced, but sometimes even that doesn't always solve that kind of writer's block.
Kaethel
(going back to fight her blank page)
