I'm not at suffering any kind of writer's block at the moment, but for those times when I do, here's a great little application which means what it says. Basically, you type for a set period of time, or pay the consequences.
It's a cool little tool which I think you could use to get into your writing each session by setting an arbitrary perdiod of time, say five minutes, and writing everything which comes to mind in that period, either around your topic, or as a cleansing brain dump. Then just copy to your clipboard, refine, prune, and re-style as you wish.
I think you could also use it as an idea generation tool by using the alocated time to just brain-storm ideas around a topic, doing so in a completely uninhibited way, then refining offline at a later point.
Either way, it's just like someone who forces your sneakers and kicks you out the door to the gym when you'd rather not go.