Write or Die

This is another one of those ideas that tap-dances on that fine line between "brilliant" and "completely mental."  Having trouble keeping yourself writing? There's an app for that:

The idea is to instill in the would-be writer with a fear of not writing. We do this by employing principles taught in Introduction to Psychology. Anyone remember Operant Conditioning and Negative Reinforcement? [...]

Write or Die is a web application that encourages writing by punishing the tendency to avoid writing. Start typing in the box. As long as you keep typing, you're fine, but once you stop typing, you have a grace period of a certain number of seconds and then there are consequences [...]

Gentle Mode: A certain amount of time after you stop writing, a box will pop up, gently reminding you to continue writing.
Normal Mode: If you persistently avoid writing, you will be played a most unpleasant sound. The sound will stop if and only if you continue to write.
Kamikaze Mode: Keep Writing or Your Work Will Unwrite Itself

– Write or Die by Dr Wicked » About.

There's a web-based version, a desktop version, and I'm pretty sure there's an iPad version coming soon, too.  When I first heard about this, I thought it was just kind of a joke, or an art-piece proof-of-concept, but no, I've read accounts from several people who say it's really helped their productivity, so there you are.  If you need someone to crack the whip for you, you might give it a try.