In the words of Mark Twain,
If you invent two or three people and turn them loose in your manuscript, something is bound to happen to them -- you can't help it; and then it will take you the rest of the book to get them out of the natural consequences of that occurrence, and so first thing you know, there's your book all finished up and never cost you an idea.
If that's not helpful, then here's what I do for a writer's block; call someone up and ask them to name a few topics in general. Write those down, and then develop a plot or an outline for each of them. Then I start writing each of those things in full. If, by that time, I haven't had any new ideas on things that I actually want to write about, I sit down read a book, watch a movie, listen to music, and, if I can, try to hold a conversation. If you really want to get outrageous, try doing something passive with your arms and legs.
My theory behind this is that an idea is foundational, and a building is built on top of that foundation (this is the story or essay content). Sometimes, when you don't have enough discipline, a lot of crap is built on the building, and it keeps you from building further (this is the point of writer's block). By doing all these somewhat stimulating things at once, you are overloading the crap areas of the building, and those parts will eventually collapse, leaving the original building.
Hope that helps!