Ten Things to Help Restore Your NaNoWriMojo
Change Locations: Moving your writing to another space may eliminate whatever is distracting you. Think of an alternative place that is different from where you're writing now (i.e., if you're hanging out in a busy coffeeshop and getting nothing written, try the quiet room at your local library. Or if your quiet spot at home isn't working, try a busy coffeeshop.) If weather permits, find an outdoor space (the backyard, a park, a lake, the beach, etc.) where you can commune a little with nature while you write.
Clean Something: Vacuuming a room, doing a load of laundry or even tidying up your writing space restores order to some part of your immediate environment and, unless you like being a slob, makes you feel better about it. That good feeling can carry over into the work once you start writing again.
Emergency Reward: Often that carrot you've hung over the finish line seems too far away, so set up one that's a bit closer. Promise yourself a small reward for just making your writing goal today. Make it something good, too; the more you want it, the more you're likely to work for it.
Exercise: Another good way to vent some frustration is to get moving: take a walk, go to the gym, jog around the block, put on that workout DVD and follow along for twenty minutes, etc. Your goal is to work up a sweat, then take a warm shower and get back to the writing (hopefully in a more relaxed, refreshed state.)
Make Something Minty: Mint is naturally soothing, so drinking a cup of mint-flavored tea, chewing a stick of mint gum or otherwise indulging in a mint treat may bump you from crabby to calm.
Muse with Music: Play your favorite CD while you sit and relax for ten minutes. Don't think about anything; just listen. If you have a soundtrack made up for your story, that's a good choice -- or just listen to the sort of music that puts you in a positive mood. If you can write with the music playing, take it back with you and listen while you work.
Project Switch: This is one of my personal mojo restorers; I stop work on one project and write on another for a short period of time. I always switch to something I enjoy writing but I'm not especially invested in so it doesn't steal me away from my NaNo novel.
Scene Skip: At least once a week without fail I hit a scene that for whatever reason I can't write. If this happens to you, instead of letting it become a brick wall between you and the rest of your story, skip it and go work on the next scene. Mark the place in your manuscript with a notation [I use square brackets and a one-line description of the scene like this] so you can easily go back and write it later.
Switch Creative Gears: This past weekend I had a particularly dreary writing day during which I fought to get every word on the page. I took regular ten minutes breaks and used them to work on a small quilting project. Switching gears like that gave me little creative/spiritual boosts, which kept me from giving up.
Write Past It: This last idea is tough, but if writing stories was easy everyone could do it. You just keep writing. Doesn't matter how well you write, or if anything you do write will be salvageable. You're not going to think about how you're writing because you're going to be too busy writing. Keep working and moving forward with the story until your mojo returns (and yes, if you push on it generally does. If it doesn't, you can always edit brilliantly.)